fly-by-night vs temporary

fly-by-night and temporary both are nouns.

Word	Noun	Adjective	Verb	Adverb
fly-by-night	Yes	Yes	No	No
temporary	Yes	Yes	No	No

fly-by-night (noun)	temporary (noun)
a debtor who flees to avoid paying	a worker (especially in an office) hired on a temporary basis

fly-by-night (adjective)	temporary (adjective)
ephemeral	not permanent; not lasting
(of businesses and businessmen) untrustworthy or undependable	lacking continuity or regularity