Jeanine Biocic appeals her conviction for violating a United States Fish and Wildlife regulation, 50 C.F.R. § 27.83, by going partially nude in a national wildlife refuge. She contends on various grounds that the regulation is unconstitutional as applied to her. We affirm the conviction.
I
On a summer day in June of 1989, Ms. Biocic, an adult female, was walking on the beach on the Chincoteague National Wildlife Refuge in Accomack County, Virginia, with a male companion. “To get some extra sun,” as she put it, she removed the top of her two-piece bathing suit, fully exposing her breasts. She was observed in this state of partial nudity by an officer of the federal Fish and Wildlife Service who issued her a summons charging a violation of 50 C.F.R. § 27.83, which provides that
[a]ny act of indecency or disorderly conduct as defined by State or local laws is prohibited on any national wildlife refuge.
A magistrate judge convicted Ms. Biocic of violating this regulation after a trial in which the facts above summarized were established without essential dispute. Specifically, the magistrate judge concluded that Ms. Biocic’s conduct constituted an “act of indecency” within the meaning of § 9.3 of the Accomack County Code. In relevant part, that “anti-nudity” ordinance, following a Preamble which recites that the enacting body “deems it necessary to prohibit certain conduct ... in order to secure and promote the health, safety and general welfare of the [county’s] inhabitants,” makes it
unlawful for any person to knowingly, voluntarily, and intentionally appear ... in a place open to the public or open to public view, in a state of nudity.
“State of nudity” is then defined in a definitional section as
a state of undress so as to expose the human male or female genitals, pubic area or buttocks with less than a fully opaque covering, or the showing of the female breast with less than a fully opaque covering on any portion thereof below the top of the nipple.
*114“Nudity” as thus defined is expressly excluded from the ordinance’s reach when practiced in dramatic productions and other forms of legitimate artistic expression.1
The magistrate judge concluded that Ms. Biocic’s exposure of her breasts in a way which fell within the County Code’s express prohibition of this form of nudity constituted an “act of indecency” as defined by local law, hence violated the federal regulation. He fined her $25.00.
This conviction was affirmed on appeal to the United States District Court, 730 F.Supp. 1364, and Ms. Biocic then took this appeal.
II
At various stages of this case, Ms. Biocic has raised a number of challenges, constitutional and non-constitutional, to the application of this federal regulation, assimilating the local law’s definition of prohibited conduct, to convict her. These seem to have included a first amendment over-breadth claim, a due process vagueness claim, an equal protection claim, and a hybrid “privacy-penumbra”/ninth amendment claim. On this appeal, she seems to have confined her challenges to: (1) a claim of vagueness, in violation of the due process clause; (2) a claim of denial of equal protection in violation of the due process clause; and (3) a claim apparently grounded in the privacy jurisprudence of Griswold v. Connecticut, 381 U.S. 479, 85 S.Ct. 1678, 14 L.Ed.2d 510 (1965), and Roe v. Wade, 410 U.S. 113, 93 S.Ct. 705, 35 L.Ed.2d 147 (1973), which specifically invokes the ninth amendment’s “guarantee of personal liberty rights.”
We take these in the order listed.
A
The vagueness claim may have both constitutional and non-constitutional prongs. Both (if there be two) are grounded in the point that § 9.3 of the local ordinance does not purport to punish “indecency,” but only “public nudity,” which in turn it nowhere defines as “indecency.” From this, the literalist argument runs, the conduct which § 9.3 proscribes may not properly be considered “an act of indecency ... as defined by local law” within contemplation of 50 C.F.R. § 27.83.
Whether considered as merely a non-constitutional lenity argument, or as one asserting due process vagueness (the government’s interpretation), we are not persuaded by it.
The issue, viewed from either perspective, is whether one clearly on notice that local law proscribes the exact state of semi-nudity conceded here is fairly on notice that it may also be proscribed by the federal regulation as an “act of indecency” within contemplation of the local law.
This question is subject to any amount of semantic quibbling, and has produced a good deal here, but in the end we agree with the magistrate judge that “common sense” compels an affirmative answer. Indeed, the legal test of statutory vagueness is one that is expressed essentially in terms of common sense. This stems from the reason for the law’s special concern with ambiguity in criminal statutes: that such laws must “give the person of ordinary intelligence a reasonable opportunity to know what is prohibited.” Master Printers of America v. Donovan, 751 F.2d 700, 710 (4th Cir.1984) (quoting Grayned v. City of Rockford, 408 U.S. 104, 109, 92 S.Ct. 2294, 2299, 33 L.Ed.2d 222 (1972)).
Given the ultimate ambiguity of any written text, the test whether a particular one is sufficiently ambiguous that it fails to give such an opportunity — is impermissi-bly “vague” — is necessarily a practical rather than hypertechnical one. It asks the commonsensical question whether the text “conveys sufficiently definitive warning as to the proscribed conduct when measured by common understanding and practices.” Master Printers of America, 751 F.2d at 711 (quoting United States v. Pe-trillo, 332 U.S. 1, 8, 67 S.Ct. 1538, 1542, 91 *115L.Ed. 1877 (1947)). This test of course necessarily assumes a person of ordinary intelligence who is aware of the text (ignorance of it being “no excuse”).
To apply the test here, we therefore start by assuming a person of ordinary intelligence looking at these two texts for guidance as to permitted and prohibited conduct within the Chincoteague National Wildlife Refuge. And we ask the question whether such a person, reading these texts in the light of “common understanding and practice,” would be sufficiently warned that fully exposing female breasts in “a place open to public view” was prohibited by the federal regulation because it was implicitly identified in the county ordinance as an “act of indecency.”
We think, as did the magistrate judge and the district judge, that only a person refusing to apply common understanding in the matter would fail to be so warned. In common understanding and practice the only reason for prohibiting public nudity by law is because of the perception (right or wrong) that it is “indecent.” No other reason is apparent in common understanding and practice in this society. The “plain meaning,” see United States v. Ron Pair Enterprises, Inc., 489 U.S. 235, 109 S.Ct. 1026, 1030, 103 L.Ed.2d 290 (1989), of the word “indecency” includes the notions of being “[ojffensive to common propriety; offending against modesty or delicacy____” Black’s Law Dictionary 691 (5th ed. 1979). It is therefore inconceivable that a person of ordinary intelligence in this society (whatever might be the case elsewhere) would fail to appreciate that an ordinance banning public nudity did so because it was considered “offensive to common propriety ... and against modesty,” hence, by commonly accepted definition of the term, was thought to be “indecent.” Only willful blindness could fail to appreciate that; and willful blindness is no more an excuse than bald ignorance. Cf. South Florida Free Beaches v. City of Miami, 734 F.2d 608, 611 (11th Cir.1984) (word indecent “certainly applies to public nudity”).
These texts, construed together under the appropriate test, sufficiently warn that public nudity such as that conceded here is prohibited by the federal regulation, hence do not offend due process guarantees nor invoke principles of lenity in the construction of the regulation’s reach.
B
Ms. Biocic’s equal protection claim2 is equally simple: the ordinance (hence, presumably, the federal regulation that assimilates its “definition” of indecency) prohibits the public exposure of female breasts but not male breasts; this constitutes a gender-based distinction that is not substantially related to an important governmental interest, hence fails the appropriate intermediate level of scrutiny in equal protection analysis.
We assume, without deciding, as did the district court, that a distinction based upon anatomical differences between male and female is gender-based for equal protection analysis purposes.3 But we then agree with the district court that the distinction here is one that is substantially related to an important governmental interest, hence does not deny equal protection.
The important government interest is the widely recognized one of protecting the moral sensibilities of that substantial segment of society that still does not want to be exposed willy-nilly to public displays of various portions of their fellow citizens’ anatomies that traditionally in this society *116have been regarded as erogenous zones. These still include (whether justifiably or not in the eyes of all) the female, but not the male, breast.4
That does it, for the limited purpose of our legal inquiry. As Justice Stewart put it:
[W]e have recognized that in certain narrow circumstances men and women are not similarly situated; in these circumstances a gender classification based on clear differences between the sexes is not invidious, and a legislative classification realistically based upon those differences is not unconstitutional.
Michael M. v. Sonoma County Superior Court, 450 U.S. 464, 478, 101 S.Ct. 1200, 1209, 67 L.Ed.2d 437 (1981) (Stewart, J., concurring).
C
Ms. Biocic’s final challenge, as indicated, seeks to invoke the ninth amendment’s “guarantee of personal liberty rights,” in particular the rights to privacy and personhood famously recognized in the line of cases represented by Griswold v. Connecticut, 381 U.S. 479, 85 S.Ct. 1678, 14 L.Ed.2d 510 (1965), and Roe v. Wade, 410 U.S. 113, 93 S.Ct. 705, 35 L.Ed.2d 147 (1973).5
Though she attempts to narrow her claim to protection of the particular (“discrete”) way in which she acted, her essential effort is to equate a right to public nudity at the whim of the actor to the profound rights of personhood and privacy recognized in Gris-wold and Roe. To do so, she invites our attention to the similarity between the feelings of “wholesomeness,” “peace of mind in being in the natural,” and “free-spiritedness” which her discrete and only partial nudity gave her, and the comparable feelings of well-being and freedom protected as fundamental liberty interests in Gris-wold (right to use of contraceptives), and Roe v. Wade (right to abortion). This is a valiant and colorful try, but it has long been flatly rejected, see, e.g., Richards v. Thurston, 424 F.2d 1281, 1285 (1st Cir.1970) (“the right to appear au nature! at home is relinquished when one sets foot on a public sidewalk”); L. Tribe, American Constitutional Law 1412 (1988) (no right to appear nude “on the main street at high noon”); see also Roth v. United States, 354 U.S. 476, 512, 77 S.Ct. 1304, 1323, 1 L.Ed.2d 1498 (1957) (Douglas, J., dissenting) (“No one would suggest that the First Amendment permits nudity in public places”), and we are not prepared to depart from that view of the matter at this point.
AFFIRMED
. As Ms. Biocic's brief notes, this ordinance was adopted in 1984 to deal with a growing problem of nudity in public areas of the Refuge. The Refuge was then attracting upwards of 2,000,-000 visitors a year, many of whom found the conduct objectionable.
. This claim was erroneously ascribed by Ms. Biocic to the fourteenth amendment’s protection. Because it challenges federal rather than state law, it should of course have been asserted under the due process clause of the fifth amendment. Bolling v. Sharp, 347 U.S. 497, 499, 74 S.Ct. 693, 694, 98 L.Ed. 884 (1954). The error in assumption is of no moment, however; the analysis is essentially the same under either source.
. The government argues that because the anatomical differences between male and female make the two incapable of "equal” treatment in the respect at issue, there is no denial of equal protection; that this is simply unequal treatment of unequals, which does not involve invidious discrimination. See Wood v. Mills, 528 F.2d 321, 323 (4th Cir.1975). We pass the issue for purposes of this appeal.
. Ms. Biocic attacks the basic premise that this is an accurate assessment of the current state of moral sensibilities on the matter. She cites in support of the contrary proposition a number of extra-legal sources, including Sports Illustrated, that seem to indicate a growing, perhaps already achieved, acceptance by many of the "state of nudity” here in issue. And she points to the undeniable fact that the female breast has from time immemorial been the subject of high artistic expression in great, publicly displayed sculpture and painting.
That public morals are not static in this realm, and that artistic depictions of the female breast have indeed long been accepted, cannot be gainsaid. But for our limited purpose— which is only to inquire whether intentional exposure of the full female breast in public places at the whim of the actor is at this time constitutionally protected against any governmental restrictions — the two points are beside the point.
. We need not quibble with Ms. Biocic’s apparent view that the ninth amendment is itself a source of those rights; it has been recognized as at least the source of a rule against cramped construction of rights specifically enumerated elsewhere. See Griswold, 381 U.S. at 486-99, 85 S.Ct. at 1684-90 (Goldberg, J., concurring).