questionable vs suspect

questionable is not a noun while suspect is a noun.

Word	Noun	Adjective	Verb	Adverb
questionable	No	Yes	No	No
suspect	Yes	Yes	Yes	No

questionable (noun)	suspect (noun)
	someone who is under suspicion
	a person or institution against whom an action is brought in a court of law; the person being sued or accused

questionable (adjective)	suspect (adjective)
subject to question	not as expected
able to be refuted

questionable (verb)	suspect (verb)
	regard as untrustworthy; regard with suspicion; have no faith or confidence in
	imagine to be the case or true or probable
	hold in suspicion; believe to be guilty