hard core vs coterie

hard core and coterie both are nouns.

Word	Noun	Adjective	Verb	Adverb
hard core	Yes	No	No	No
coterie	Yes	No	No	No

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

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

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

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