curious vs questioning

curious is not a noun while questioning is a noun.

Word	Noun	Adjective	Verb	Adverb
curious	No	Yes	No	No
questioning	Yes	Yes	No	No

curious (noun)	questioning (noun)
	a request for information

curious (adjective)	questioning (adjective)
eager to investigate and learn or learn more (sometimes about others' concerns)	showing curiosity
beyond or deviating from the usual or expected	marked by or given to doubt
	perplexed (as if being expected to know something that you do not know)