Female students coming to office hours in overly revealing clothing [because this is potentially relevant, I'm a 37 y/o male]

Being the end of the semester, I've had a bunch of students come to my office hours to ask questions about things I'm responsible for. Among them, there have been a small number of female undergrads that have shown up wearing the kind of clothing that I think is inappropriate for a meeting with a faculty member. I'm not a prude (I hope), but I feel there is something amiss when a 20 y/o undergrad wants to discuss course validation from a neighboring university and then she goes and sits in front of me wearing booty shorts and a very see-through t-shirt (or a tanktop so skimpy that half her bra shows no matter what, or... take your pick). Before someone says anything to the effect, yes, it's summer, but it is not that warm (we're having a nice 20-25 C average these days).

In short, how can I tell these women, politely, that they should think twice about showing up half naked to meetings with faculty members?

Note that I'm not implying that I'm feeling sexually harassed or anything along those lines. Without getting into details, I'm old enough and happily married enough that I don't find college girls sexually appealing anymore. What I'm looking for is a way of telling them meetings with people higher up in the hierarchy have implicit standards, including some pertinent to what you may and may not wear that doesn't sound like a crude rephrasing of oh please why don't you cover up you filthy [censored].
Does your institution have a student dress code?
Does your location have public indecency laws?

If their clothing violates either, refuse meetings until the problem is corrected.

Otherwise, ignore their appearance and carry on as usual.



Their sense of appropriate dress is clearly different from yours, but like political or religious opinions, such senses are often personal and cultural.  For all you know, a bikini is her preferred set of comfortable clothing.  Without a clear agreed-upon set of rules to defer to, such opinions are unproductive to dispute.  Let it be.