Antonyms of adj unostentatious

2 senses of unostentatious

Sense 1
unostentatious (vs. ostentatious), unpretentious, unpretending -- (not ostentatious; "his unostentatious office"; "unostentatious elegance")

ostentatious (vs. unostentatious), pretentious -- (intended to attract notice and impress others; "an ostentatious sable coat")
        => flaunty -- (inclined to flaunt)
        => flamboyant, showy, splashy -- (marked by ostentation but often tasteless; "a cheap showy rhinestone bracelet"; "a splashy half-page ad")

Sense 2
understated, unostentatious, unpretentious -- (exhibiting restrained good taste; "the room is pleasant and understated")

INDIRECT (VIA tasteful) -> tasteless -- (lacking aesthetic or social taste)

Similarity of adj unostentatious

2 senses of unostentatious

Sense 1
unostentatious (vs. ostentatious), unpretentious, unpretending -- (not ostentatious; "his unostentatious office"; "unostentatious elegance")
       => quiet, restrained -- (not showy or obtrusive; "clothes in quiet good taste")

Sense 2
understated, unostentatious, unpretentious -- (exhibiting restrained good taste; "the room is pleasant and understated")
       => tasteful (vs. tasteless) -- (having or showing or conforming to good taste)