unbecoming vs unseemly

unbecoming and unseemly both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unbecoming	No	Yes	No	No
unseemly	No	Yes	No	No

As adjectives, unbecoming and unseemly are synonyms defined as:

unbecoming and unseemly: not in keeping with accepted standards of what is right or proper in polite society

Other synonyms of unbecoming include indecent, indecorous, uncomely, untoward.

unbecoming (adjective)	unseemly (adjective)
not in keeping with accepted standards of what is right or proper in polite society	not in keeping with accepted standards of what is right or proper in polite society