questioning vs curious

questioning is a noun but curious is not a noun.

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

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

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