This appeal concerns the interpretation and constitutionality of the Iowa criminal trespass legislation, chapter 274, Acts of the Sixty-fourth General Assembly (1971), now chapter 729, The Code, 1975.
Defendant pled not guilty to an information filed in Waterloo Municipal Court charging him with criminal trespass upon Waterloo school district property which resulted in damages exceeding $100. See § 729.3, The Code. Following his motion for change of venue, trial was held in Cedar Rapids Municipal Court. The jury returned a guilty verdict. Defendant was sentenced to four months’ imprisonment, suspended upon one year’s good behavior, and fined $100 payable in 30 days. He has appealed from this judgment. We affirm.
Our careful study of the transcript and record discloses substantial evidence from which the jury could have found the following facts.
At all times pertinent here the student body at West Junior High in Waterloo included over 1000 white and about 45 black students. An elderly speech teacher there distributed a story, “Little Brown Koko” to some speech class members as supplementary material to be used for oral work within the class.
The use of this story first came to the attention of the administrators at West Junior High on May 22 or May 23, 1972. In a classic understatement, it was described by the Waterloo superintendent as “inappropriate material to be used in schools today in Waterloo or any place else.” A black school administrator (home-school community relations director) met with the teacher and parents of the children involved. The objectionable material was removed. An apology was made to the parents.
When the incident came to defendant’s attention he, accompanied by parents of school children, visited the speech teacher’s classroom on May 24. Defendant testified he wanted her fired and “we insisted on whatever was going to be done that it be done in writing from the superintendent’s office.” Although class was in session, defendant and those accompanying him remained there until they received a letter from the superintendent’s office notifying them the teacher had been suspended for the remainder of the school year.
The following day, May 25, a number of white students, objecting to the teacher’s dismissal, staged a sit-down in the school halls. The principal’s attempt to talk out the problem in the school auditorium was unsuccessful. At approximately 10:00 A.M. school was dismissed for the day.
Defendant and several concerned parents had gone to West Junior High that morning. They eventually proceeded to the principal’s office to discuss the safety of black students and to secure transportation for them to the “east side”. Defendant testified the school superintendent responded there were 1100 white students running the streets whom he “had to see about.” Nonetheless, a school bus arrived and transported the black students to an apparently pre-arranged destination, the “community enabler’s office” on the east side of Waterloo.
In the afternoon defendant and others met at a city park. According to defendant, it was decided the group would “go and visit him [the superintendent] at his office for the conference that we did not have that morning.” Defendant testified there were three reasons for taking this action: 1) parents’ concern for the safety of their children and the materials being taught, 2) defendant’s feeling his own children needed the protection of the superintendent, and 3) *305the constitutional right to “carry their grievances to the seat of the government.”
Defendant led 50 or 60 persons to the school administration building and into the superintendent’s office. The secretary testified they ignored her request to sit in a large adjoining board meeting room. Defendant presented to the superintendent a written demand that the speech teacher be fired, the principal be fired, and a program of human relations be instituted. Defendant told the superintendent he should “initiate the follow-through.” The defendant and his companions packed themselves into the small offices of the secretary and superintendent, filling every available space.
After a while the superintendent started to leave to attend a school board meeting he had called to study the demands, “at which time I was told that I should stay in my office by the defendant until such time as this could be initiated from within my office.” The door was blocked by defendant’s companions. Defendant and others were a human carpet on the floor. Defendant testified he told the superintendent, “Don’t step on the brothers or the sisters.” The superintendent’s telephone was placed in a wastebasket and one of the demonstrators sat on it. The secretary’s telephone was taken from her desk and partially disassembled.
Waterloo police who came to the secretary’s door were told by these occupants “You can’t come in.” The police requested the superintendent be allowed to come out and received the response, “You’re not coming in and he’s not coming out.” The officers who had gotten the door partly open were then pushed out and the door was shut.
At about 6:00 P.M. an assistant county attorney, using a bullhorn, informed the insiders they had to vacate the premises and free the superintendent within 20 minutes or face criminal trespass charges. Defendant announced that anyone on parole or probation and anyone else who did not wish to be arrested should leave.
In the words of one police officer “there were wall-to-wall people” in the hallway outside the secretary’s door. Apparently sensing a hazard there, police took over the adjoining board meeting room and attempted to force an interior door to the superintendent’s office. Persons inside broke the legs off a coffee table and with defendant’s help used this and other available furniture to barricade the door.
When the time limit expired the police unsuccessfully attempted to push the door open, then gained entrance to the offices by sawing through the door. By then the demonstrators had retreated through the secretary’s door to the building’s lobby.
The police and the county attorney proceeded to the lobby where the latter read a district court injunction. The demonstrators were given five minutes to clear the premises. After expiration of this period the remaining persons were peacefully escorted from the building. Defendant was taken to the police station and charged with criminal trespass.
The occupation of the school offices resulted in damage to the rooms and furniture. A lamp was chipped, a coffee table broken, draperies were torn down, furniture was overturned, typewriter ribbons unrolled, supplies scattered, and papers damaged and strewn about. The carpet needed cleaning. Repair and cleanup costs totaled several hundred dollars. In addition, the superintendent and his secretary accomplished no productive work during the sit-in.
I. Section 729.1 provides:
“729.1 Criminal trespass. Definitions:
1. The term ‘property’ shall include any land, dwelling, building, conveyance, vehicle, or other temporary or permanent structure whether publicly or privately owned.
2. The term ‘trespass’ shall mean one or more of the following acts.
a. Entering upon or in property without legal justification or without the im*306plied or actual permission of the owner, lessee, or person in lawful possession with the intent to commit a public offense or to use, remove therefrom, alter, damage, harass, or place thereon or therein anything animate or inanimate, without the implied or actual permission of the owner, lessee, or person in lawful possession.
b. Entering or remaining upon or in property without legal justification after being notified or requested to abstain from entering or to remove or vacate therefrom by the owner, lessee, or person in lawful possession, or the agent or employee of the owner, lessee, or person in lawful possession, or by any peace officer, magistrate, or public employee whose duty it is to supervise the use or maintenance of the property.
c. Entering upon or in property for the purpose or with the effect of unduly interfering with the lawful use of the property by others.
d. Being upon or in property and using, removing therefrom, altering, damaging, harassing, or placing thereon or therein anything animate or inanimate, without the implied or actual permission of the owner, lessee, or person in lawful possession.”
Defendant contends 1) the phrase “without legal justification,” and the words “harass”, “harassing” and “unduly” are unconstitutionally vague; 2) §§ 729.1(2)(b) and 729.1(2)(c) are overbroad in that they may apply to activity protected by the First and Fourteenth Amendments to the United States Constitution.
II. It is clear defendant’s conduct was of a type subject to state regulation. The record demonstrates his activity would be prohibited under any construction of the statute. See Broadrick v. Oklahoma, 413 U.S. 601, 608, 93 S.Ct. 2908, 2914, 37 L.Ed.2d 830, 837-838 (1973).
We flatly reject defendant’s argument the exercise of his First Amendment rights was reasonable. The First Amendment has never licensed destruction of property or imprisonment of public officials. See Cox v. Louisiana, 379 U.S. 536, 554-555, 85 S.Ct. 453, 464, 13 L.Ed.2d 471, 484 (1965); Hurley v. Hinckley, 304 F.Supp. 704, 709-710 (D.Mass.1969), aff’d, Doyle v. O’Brien, 396 U.S. 277, 90 S.Ct. 603, 24 L.Ed.2d 469 (1970).
Ordinarily one to whom a statute is constitutionally applied will not be allowed to attack the statute on the grounds it might be unconstitutionally applied to others. United States v. Raines, 362 U.S. 17, 21, 80 S.Ct. 519, 522, 4 L.Ed.2d 524, 529 (1960). But traditional rules of standing are relaxed to permit a defendant whose conduct admittedly falls within a statute to challenge an enactment as overbroad because of the “danger of tolerating, in the area of First Amendment freedoms, the existence of a penal statute susceptible of sweeping and improper application.” Dombrowski v. Pfister, 380 U.S. 479, 486-487, 85 S.Ct. 1116, 1121, 14 L.Ed.2d 22, 28-29 (1965), quoting NAACP v. Button, 371 U.S. 415, 433, 83 S.Ct. 328, 338, 9 L.Ed.2d 405, 418 (1963). Under this exception to the traditional rule, we recognize defendant’s standing to challenge the constitutionality of § 729.1, supra.
III. Our rules which act to support statutes under constitutional attack were summarized in State v. Aldrich, 231 N.W.2d 890, 894 (Iowa 1975) and State v. Kueny, 215 N.W.2d 215, 216-217 (Iowa 1974) and need not be repeated here.
In determining whether Iowa’s criminal trespass legislation is vague or over-broad we note the principle that if a statute “can be made constitutionally definite by a reasonable construction, * * * this Court is under a duty to give the statute that construction.” United States v. Harriss, 347 U.S. 612, 618, 74 S.Ct. 808, 812, 98 L.Ed. 989, 996-997 (1954); State v. Lavin, 204 N.W.2d 844, 849 (Iowa 1973); State v. Ramos, 260 Iowa 590, 596, 149 N.W.2d 862, 865 (1967). We do not search for intolerable lengths to which the unconstrued stat*307ute might be extended; rather we confine the language and thereby give effect to its provisions. Von Weidlein International, Inc. v. Young, 16 Ore.App. 81, 96, 517 P.2d 295, 298 (1973). This principle is followed even where the statute, if literally applied, would succumb to constitutional attack on grounds of vagueness and overbreadth. Braxton v. Municipal Court, 10 Cal.3d 138, 144, 514 P.2d 697, 700,109 Cal.Rptr. 897, 900 (1973).
IV. Defendant first argues the words “harass” and “harassing” are unconstitutionally vague.
A statute offends the Due Process Clause if it does not give a person of ordinary intelligence a reasonable opportunity to know what is prohibited so that he may act accordingly. It meets the constitutional test if the meaning of the words used can be fairly ascertained by reference to similar statutes, other judicial determinations, reference to the common law, to the dictionary, or if the words themselves have a common and generally-accepted meaning. State v. Aldrich, supra at 894.
In Webster’s Third New International Dictionary, page 1031, “harass” is defined as “to lay waste;” “to worry and impede by repeated attacks;” “to tire out;” “to vex, trouble, or annoy continually or chronically.” Each alternative involves some overt, intentional, persistent action. Unknowing harassment is precluded. It follows that the evils of a vague enactment do not inhere in the use of the word harass. In proscribing harassment, the statute regulates conduct; it does not encompass constitutionally protected speech or activity, as we have noted in division V. As so interpreted and limited, it does not encourage discriminatory enforcement, inhibit the exercise of First Amendment freedoms or serve as a trap for the innocent. See Grayned v. City of Rockford, 408 U.S. 104, 108-109, 92 S.Ct. 2294, 2298-2299, 33 L.Ed.2d 222, 227-228 (1972).
The only decision we have found weighing the word “harass” on the void-for-vagueness scale is State v. Sallinger, 11 Ore.App. 592, 504 P.2d 1383 (1972). The Oregon court upheld that state’s harassment statute in face of a similar constitutional attack.
Defendant relies on Coates v. Cincinnati, 402 U.S. 611, 91 S.Ct. 1686, 29 L.Ed.2d 214 (1971), in which the court found unconstitutional an ordinance making it a criminal offense for “three or more persons to assemble * * * and * * * conduct themselves in a manner annoying to persons passing by * * *.” Because the state court had not restrictively construed the ordinance and it contained no guiding standards, the court found it vague and overbroad. 402 U.S. at 614, 91 S.Ct. at 1688, 29 L.Ed.2d at 217.
The Coates ordinance is not comparable to chapter 729, The Code. The word “harass” connotes some intentional, continued action, while the word “annoying” does not.
We think a person of ordinary intelligence would recognize a distinction between an intentional harassment in a chapter 729 context, and conduct on a public street which might inadvertently annoy passersby. It is the same distinction Mr. Justice Holmes analogously referred to when he said even a dog distinguishes between being stumbled over and being kicked. A person doing the stumbling or kicking has less trouble recognizing the difference. Even defendant, describing the deplorable cqnduct of white children at the school auditorium meeting in shouting at and throwing papers at the black children, readily concluded the latter were “being harassed.”
It should also be noted the word “harass” does not stand alone in chapter 729 as did the term “annoying” in the Coates ordinance; “harass” takes its coloration from other terms in the enactment, State v. Aid-rich, supra at 895, and thus acquires a more specific meaning because of its context.
Our conclusion has already been summarized in CSC v. Letter Carriers, 413 U.S. *308548, 578-579, 93 S.Ct. 2880, 2897, 37 L.Ed.2d 796, 816 (1973):
“[T]here are limitations in the English language with respect to being both specific and manageably brief, and it seems to us that although the prohibitions may not satisfy those intent on finding fault at any cost, they are set out in terms that the ordinary person exercising ordinary common sense can sufficiently understand and comply with, without sacrifice to the public interest.”
As above defined and limited, we hold the words “harass” and “harassing” are not unconstitutionally vague. The acts of defendant fell squarely within the plain meaning of those terms. We find no error here.
V. Defendant next asserts the phrase “without legal justification” is so vague it does nothing to limit the application of § 729.1(2)(a) or (b), The Code, supra.
We find persuasive here the court’s rationale in Hurley v. Hinckley, supra, in which the words “without right” in a criminal trespass statute were challenged as vague and overbroad. The federal court held the words mean “without legal right,” and legal right “includes any right of the plaintiffs, individually or collectively, found in the Constitution of the United States.” 304 F.Supp. at 710. Thus the phrases “without right” and “without legal justification” expressly allow and protect entry on public property for the purpose of reasonably exercising First Amendment rights. See Dunkel v. Elkins, 325 F.Supp. 1235, 1241 (D.Md.1971), where the court, construing a statute which referred to persons who have “no lawful business to pursue,” held that “lawful business” is any activity constitutionally protected.
Defendant relies on Thornhill v. Alabama, 310 U.S. 88, 60 S.Ct. 736, 84 L.Ed. 1093 (1940), where the court struck down as unconstitutional a statute which prohibited, without a just cause or legal excuse, loitering about a place of business with the intent to influence or induce others not to deal with that business. But Thornhill is distinguishable because that statute, on its face, prohibited constitutionally protected speech. Iowa’s trespass enactment, in contrast, regulates conduct. The First and Fourteenth Amendments have never afforded the same kind of freedom to those who would communicate ideas by conduct as those who would communicate ideas by pure speech. Cox v. Louisiana, supra, 379 U.S. at 555, 85 S.Ct. at 464-465, 13 L.Ed.2d at 484. We are convinced our above construction of the language “without legal justification” is constitutionally acceptable in the specific context of a criminal trespass enactment.
VI. Defendant argues § 729.1(2)(c) is vague and overbroad because the word “unduly” has no ascertainable meaning and consequently no limiting effect on “interfering”.
The word “undue” is defined in Black’s Law Dictionary, page 1697, as “more than necessary; not proper; illegal.” Webster’s Third New International Dictionary, page 2492, defines “unduly” as “excessively”. Thus under § 729.1(2)(c) one cannot unnecessarily, improperly, illegally or excessively interfere with the lawful use of property.
In Cameron v. Johnson, 390 U.S. 611, 88 S.Ct. 1335, 20 L.Ed.2d 182 (1968), a vagueness challenge was made to a statute prohibiting picketing or mass demonstrations which “obstruct or unreasonably interfere” with ingress and egress at a public premises. The court said:
“The terms ‘obstruct’ and ‘unreasonably interfere’ plainly require no ‘guess[ing] at [their] meaning’. Appellants focus on the word ‘unreasonably’. It is a widely used and well understood word and clearly so when juxtaposed with ‘obstruct’ and ‘interfere.’” — 390 U.S. at 616, 88 S.Ct. at 1338, 20 L.Ed. at 187.
We hold the words “unduly interfering”, when so coupled, sufficiently apprise a person of common intelligence of the proscribed conduct.
*309Nor is the statute overly broad in this respect, as the State may legitimately regulate conduct which unduly interferes with lawful use of property. Squarely on point, the Supreme Court has said “the exercise of First Amendment rights may be regulated where such exercise will unduly interfere with the normal use of the public property by other members of the public with an equal right of access to it.” (Emphasis supplied.) Food Employees v. Logan Valley Plaza, 391 U.S. 308, 320-321, 88 S.Ct. 1601, 1609, 20 L.Ed.2d 603, 613 (1968).
We hold the meaning of “unduly” as used here is clear and prevents an overly broad application of § 729.1(2)(c).
We thus find no merit in any of the propositions urged by defendant, and the judgment below is affirmed.
Affirmed.
MOORE, C. J., and LeGRAND, REES, UHLENHOPP and HARRIS, JJ., concur. McCORMICK, MASON and RAWLINGS, JJ., dissent.