inquiring vs questioning

inquiring and questioning both are nouns.

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

As nouns, inquiring and questioning are synonyms defined as:

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

inquiring (adjective)	questioning (adjective)
given to inquiry	showing curiosity
	marked by or given to doubt
	perplexed (as if being expected to know something that you do not know)