transient vs short-lived

transient is a noun but short-lived is not a noun.

Word	Noun	Adjective	Verb	Adverb
transient	Yes	Yes	No	No
short-lived	No	Yes	No	No

As adjectives, transient and short-lived are synonyms defined as:

Other synonyms of transient include ephemeral, fugacious, passing, transitory.

transient (noun)	short-lived (noun)
(physics) a short-lived oscillation in a system caused by a sudden change of voltage or current or load
one who stays for only a short time

transient (adjective)	short-lived (adjective)
of a mental act; causing effects outside the mind	lasting a very short time
lasting a very short time