idol vs golden calf

idol and golden calf both are nouns.

Word	Noun	Adjective	Verb	Adverb
idol	Yes	No	No	No
golden calf	Yes	No	No	No

As nouns, golden calf is a hyponym of idol; that is, golden calf is a word with a more specific, narrower meaning than idol:

idol: a material effigy that is worshipped
golden calf: (Old Testament) an idol made by Aaron for the Israelites to worship; destroyed by Moses; it is now used to refer to anything worshipped undeservedly

Other hyponyms of idol include joss, Juggernaut.

idol (noun)	golden calf (noun)
a material effigy that is worshipped	(Old Testament) an idol made by Aaron for the Israelites to worship; destroyed by Moses; it is now used to refer to anything worshipped undeservedly
an ideal instance; a perfect embodiment of a concept
someone who is adored blindly and excessively