brain trust vs kitchen cabinet

brain trust and kitchen cabinet both are nouns.

Word	Noun	Adjective	Verb	Adverb
brain trust	Yes	No	No	No
kitchen cabinet	Yes	No	No	No

As nouns, brain trust and kitchen cabinet are synonyms defined as:

brain trust and kitchen cabinet: an inner circle of unofficial advisors to the head of a government

brain trust (noun)	kitchen cabinet (noun)
an inner circle of unofficial advisors to the head of a government	an inner circle of unofficial advisors to the head of a government