What is the word for an action that is "considered to be frowned upon"?

I'm looking for an adjective to describe a behavior or action that is considered to be a faux pas, or is frowned upon.

Picking your nose is [word].

Wearing socks with sandals is [word].

Breaking wind in an elevator is [word].

Voting this question down is [word].

_{ok, maybe not the last one...}

How about uncouth?

WordNet Search says:

S: (adj) coarse, common, rough-cut, uncouth, vulgar (lacking refinement or cultivation or taste) "he had coarse manners but a first-rate mind"; "behavior that branded him as common"; "an untutored and uncouth human being"; "an uncouth soldier--a real tough guy"; "appealing to the vulgar taste for violence"; "the vulgar display of the newly rich"

'frowned upon' sounds just right to me. It's general enough to fit all your cases. I don't think a two word locution is breaking the rules here.

Perhaps, simply inappropriate?