Most unassumed means something that is not confident, unassuming or humble. Some of the antonyms for most unassumed include flamboyant, ostentatious, confident, brazen, bold and arrogant. Flamboyant refers to something that is showy, extravagant or flashy. Ostentatious means something that is designed to impress or attract attention, usually by being gaudy or excessive. Confidence means something that is self-assured, assured, certain or secure. Brazen means something that is bold, shameless, or audacious while arrogant means something that is full of oneself, overconfident or conceited. Therefore, one can use any of these antonyms for most unassumed depending on the context of the sentence.