question vs gainsay

question is a noun but gainsay is not a noun.

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

question (noun)	gainsay (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

question (verb)	gainsay (verb)
pose a question	take exception to
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