toss away vs trash

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

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

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

toss 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

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