inappropriate (part of speech: adjective)
vulgar (part of speech: adjective)
earthy, crude, salty, philistine, cheap, degraded, low, gaudy, common, depraved, barnyard, rude, gross, unpolished, sordid, sleazy, repulsive, inelegant, homespun, animal, offensive, colloquial, shameless, tawdry, base, profane, boorish, ignoble, undignified, rough, cockney, raw, rank, crass, glaring, tactless, coarse, indelicate, ignominious, tasteless, unrefined, barbaric, brazen, scandalous, graceless, clumsy, unseemly, in bad taste, ill-bred, chintzy, coarse-grained, revolting, outlandish, brutish, obscene, vulgar, idiomatic, garish, broad
- The girl suddenly faced her mother, her pink lips thrust forward in an unbecoming pout.
- Make us feel that you could not have anything ugly or awkward or unbecoming about you. - "Stray Thoughts for Girls", Lucy H. M. Soulsby.
- I only came here to implore pardon of the noble lady of Ringstetten for my unbecoming behavior yesterday. - "Undine", Friedrich de la Motte Fouque.