funny vs questionable

funny is a noun but questionable is not a noun.

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

funny (noun)	questionable (noun)
an account of an amusing incident (usually with a punch line)

funny (adjective)	questionable (adjective)
arousing or provoking laughter	subject to question
experiencing odd bodily sensations	able to be refuted
not as expected
beyond or deviating from the usual or expected