postulate vs insist

postulate is a noun but insist is not a noun.

Word	Noun	Adjective	Verb	Adverb
postulate	Yes	No	Yes	No
insist	No	No	Yes	No

As verbs, insist is a hyponym of postulate; that is, insist is a word with a more specific, narrower meaning than postulate:

Other hyponyms of postulate include assert.

postulate (noun)	insist (noun)
(logic) a proposition that is accepted as true in order to provide a basis for logical reasoning

postulate (verb)	insist (verb)
take as a given; assume as a postulate or axiom	postulate positively and assertively
maintain or assert	be emphatic or resolute and refuse to budge
require as useful, just, or proper	beg persistently and urgently