To me this is more a question of semantics and somewhat pre-defined adjectives.....
The words "Sexy" and "Classy" imply a certain level of social acceptance just based on how they are used today. But it's just the opposite for "Slutty" and "Dirty".
Personally, I prefer my lady to be just that, a lady. But that doesn't mean she can't be a little "slutty" or a little "dirty" when we're alone doing things for each other.
Ultimately, it comes down to what a person considers "Slutty" or "Dirty".
BUT, if the point of the question is how you would think your lady might be perceived out in public, then I'm always going to want her to be looked at as "Classically Sexy".
My $0.02 and thanks for listening.