pro tem vs temporary

pro tem is not a noun while temporary is a noun.

Word	Noun	Adjective	Verb	Adverb
pro tem	No	Yes	No	Yes
temporary	Yes	Yes	No	No

pro tem (noun)	temporary (noun)
	a worker (especially in an office) hired on a temporary basis

pro tem (adjective)	temporary (adjective)
for the time being	not permanent; not lasting
	lacking continuity or regularity

pro tem (adverb)	temporary (adverb)
for the time being; temporarily