pair vs unify

pair is a noun but unify is not a noun.

Word	Noun	Adjective	Verb	Adverb
pair	Yes	No	Yes	No
unify	No	No	Yes	No

As verbs, unify is a hypernym of pair; that is, unify is a word with a broader meaning than pair:

Other hypernyms of pair include unite.

pair (noun)	unify (noun)
two people considered as a unit
a set of two similar things considered as a unit
a poker hand with 2 cards of the same value
two items of the same kind

pair (verb)	unify (verb)
engage in sexual intercourse	become one
bring two objects, ideas, or people together	join or combine
arrange in pairs	to bring or combine together or with something else
occur in pairs	act in concert or unite in a common purpose or belief
form a pair or pairs	bring together for a common purpose or action or ideology or in a shared situation