greenback vs clam

greenback and clam both are nouns.

Word	Noun	Adjective	Verb	Adverb
greenback	Yes	No	No	No
clam	Yes	No	Yes	No

As nouns, clam is a hyponym of greenback; that is, clam is a word with a more specific, narrower meaning than greenback:

greenback (noun)	clam (noun)
a piece of paper money (especially one issued by a central bank)	burrowing marine mollusk living on sand or mud; the shell closes with viselike firmness
	flesh of either hard-shell or soft-shell clams
	a piece of paper money worth one dollar

greenback (verb)	clam (verb)
	gather clams, by digging in the sand by the ocean