IPA: //ˌʌn.bɪˈkʌ.mɪŋ//
KK: /ʌnˈbɪkəmɪŋ/
Not suitable or attractive; something that does not look good or is not appropriate for someone.
She decided not to wear the unbecoming outfit to the party.
Comparative: more unbecoming
Superlative: most unbecoming
Unbecoming → It is formed from "un-" (meaning not) and "becoming" (from Old English "becuman", meaning to come or to be suitable). The word "unbecoming" means not suitable or inappropriate in appearance or behavior.
Think of 'not' ('un-') being added to 'suitable' or 'appropriate' ('becoming') — that's why unbecoming means something that is not suitable.