ruminate vs question

ruminate is not a noun while question is a noun.

Word	Noun	Adjective	Verb	Adverb
ruminate	No	No	Yes	No
question	Yes	No	Yes	No

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

Other hyponyms of ruminate include premeditate, theologise, theologize, introspect, bethink, cogitate, wonder, puzzle, consider, study.

ruminate (noun)	question (noun)
	uncertainty about the truth or factuality or existence of something
	an instance of questioning
	the subject matter at issue
	a formal proposal for action made to a deliberative assembly for discussion and vote
	a sentence of inquiry that asks for a reply
	an informal reference to a marriage proposal

ruminate (verb)	question (verb)
reflect deeply on a subject	pose a question
chew the cuds	challenge the accuracy, probity, or propriety of
	place in doubt or express doubtful speculation
	pose a series of questions to
	conduct an interview in television, newspaper, and radio reporting