get up vs attire

get up is not a noun while attire is a noun.

Word	Noun	Adjective	Verb	Adverb
get up	No	No	Yes	No
attire	Yes	No	Yes	No

As verbs, get up and attire are synonyms defined as:

get up and attire: put on special clothes to appear particularly appealing and attractive

get up (noun)	attire (noun)
	clothing of a distinctive style or for a particular occasion

get up (verb)	attire (verb)
get up and out of bed	put on special clothes to appear particularly appealing and attractive
cause to rise
put on special clothes to appear particularly appealing and attractive
develop
study intensively, as before an exam
arrange by systematic planning and united effort
raise from a lower to a higher position
rise to one's feet