transience vs brevity

transience and brevity both are nouns.

Word	Noun	Adjective	Verb	Adverb
transience	Yes	No	No	No
brevity	Yes	No	No	No

As nouns, transience and brevity are synonyms defined as:

Other synonyms of transience include briefness.

transience (noun)	brevity (noun)
an impermanence that suggests the inevitability of ending or dying	the attribute of being brief or fleeting
the attribute of being brief or fleeting	the use of brief expressions