transient vs ephemeral

transient and ephemeral both are nouns.

Word	Noun	Adjective	Verb	Adverb
transient	Yes	Yes	No	No
ephemeral	Yes	Yes	No	No

As adjectives, transient and ephemeral are synonyms defined as:

Other synonyms of transient include fugacious, passing, short-lived, transitory.

transient (noun)	ephemeral (noun)
(physics) a short-lived oscillation in a system caused by a sudden change of voltage or current or load	anything short-lived, as an insect that lives only for a day in its winged form
one who stays for only a short time

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