outfit vs attire

outfit and attire both are nouns.

Word	Noun	Adjective	Verb	Adverb
outfit	Yes	No	Yes	No
attire	Yes	No	Yes	No

As nouns, attire is a hypernym of outfit; that is, attire is a word with a broader meaning than outfit:

Other hypernyms of outfit include dress, garb.

outfit (noun)	attire (noun)
gear consisting of a set of articles or tools for a specified purpose	clothing of a distinctive style or for a particular occasion
a set of clothing (with accessories)
any cohesive unit such as a military company

outfit (verb)	attire (verb)
provide with (something) usually for a specific purpose	put on special clothes to appear particularly appealing and attractive