excogitate vs puzzle

excogitate is not a noun while puzzle is a noun.

Word	Noun	Adjective	Verb	Adverb
excogitate	No	No	Yes	No
puzzle	Yes	No	Yes	No

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

excogitate: reflect deeply on a subject
puzzle: be uncertain about; think about without fully understanding or being able to decide

Other hyponyms of excogitate include premeditate, theologise, theologize, introspect, bethink, cogitate, question, wonder, consider, study.

excogitate (noun)	puzzle (noun)
	a game that tests your ingenuity
	a particularly baffling problem that is said to have a correct solution

excogitate (verb)	puzzle (verb)
reflect deeply on a subject	be a mystery or bewildering to
come up with (an idea, plan, explanation, theory, or principle) after a mental effort	be uncertain about; think about without fully understanding or being able to decide