throw away vs trash

throw away is not a noun while trash is a noun.

Word	Noun	Adjective	Verb	Adverb
throw away	No	No	Yes	No
trash	Yes	No	Yes	No

As verbs, trash is a hyponym of throw away; that is, trash is a word with a more specific, narrower meaning than throw away:

throw away (noun)	trash (noun)
	an amphetamine derivative (trade name Methedrine) used in the form of a crystalline hydrochloride; used as a stimulant to the nervous system and as an appetite suppressant
	nonsensical talk or writing
	worthless people
	worthless material that is to be disposed of

throw away (verb)	trash (verb)
to remove	express a totally negative opinion of
throw or cast away	dispose of (something useless or old)