kitchen cabinet vs inner circle

kitchen cabinet and inner circle both are nouns.

Word	Noun	Adjective	Verb	Adverb
kitchen cabinet	Yes	No	No	No
inner circle	Yes	No	No	No

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

kitchen cabinet: an inner circle of unofficial advisors to the head of a government
inner circle: an exclusive circle of people with a common purpose

Other hypernyms of kitchen cabinet include camp, clique, coterie, ingroup, pack.

kitchen cabinet (noun)	inner circle (noun)
an inner circle of unofficial advisors to the head of a government	an exclusive circle of people with a common purpose