hard core vs inner circle

hard core and inner circle both are nouns.

Word	Noun	Adjective	Verb	Adverb
hard core	Yes	No	No	No
inner circle	Yes	No	No	No

As nouns, inner circle is a hypernym of hard core; that is, inner circle is a word with a broader meaning than hard core:

hard core: the most dedicated and intensely loyal nucleus of a group or movement
inner circle: an exclusive circle of people with a common purpose

Other hypernyms of hard core include camp, clique, coterie, ingroup, pack.

hard core (noun)	inner circle (noun)
the most dedicated and intensely loyal nucleus of a group or movement	an exclusive circle of people with a common purpose