briefly vs brief

briefly is not a noun while brief is a noun.

Word	Noun	Adjective	Verb	Adverb
briefly	No	No	No	Yes
brief	Yes	Yes	Yes	No

briefly (noun)	brief (noun)
	a condensed written summary or abstract
	a document stating the facts and points of law of a client's case

briefly (adjective)	brief (adjective)
	concise and succinct
	(of clothing) very short
	of short duration or distance

briefly (verb)	brief (verb)
	give essential information to someone

briefly (adverb)	brief (adverb)
for a short time
in a concise manner; in a few words