scrap metal vs scrap

scrap metal and scrap both are nouns.

Word	Noun	Adjective	Verb	Adverb
scrap metal	Yes	No	No	No
scrap	Yes	No	Yes	No

As nouns, scrap is a hypernym of scrap metal; that is, scrap is a word with a broader meaning than scrap metal:

Other hypernyms of scrap metal include rubbish, trash.

scrap metal (noun)	scrap (noun)
discarded metal suitable for reprocessing	the act of fighting; any contest or struggle
	a small piece of something that is left over after the rest has been used
	a small fragment of something broken off from the whole
	worthless material that is to be disposed of

scrap metal (verb)	scrap (verb)
	make into scrap or refuse
	have a disagreement over something
	dispose of (something useless or old)