in short vs in brief

in short and in brief both are adverbs.

Word	Noun	Adjective	Verb	Adverb
in short	No	No	No	Yes
in brief	No	No	No	Yes

As adverbs, in short and in brief are synonyms defined as:

Other synonyms of in short include briefly, concisely, shortly.

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