idol vs heartthrob

idol and heartthrob both are nouns.

Word	Noun	Adjective	Verb	Adverb
idol	Yes	No	No	No
heartthrob	Yes	No	No	No

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

idol (noun)	heartthrob (noun)
a material effigy that is worshipped	an object of infatuation
an ideal instance; a perfect embodiment of a concept
someone who is adored blindly and excessively