questioner vs enquirer

questioner and enquirer both are nouns.

Word	Noun	Adjective	Verb	Adverb
questioner	Yes	No	No	No
enquirer	Yes	No	No	No

As nouns, questioner and enquirer are synonyms defined as:

Other synonyms of questioner include asker, inquirer, querier.

questioner (noun)	enquirer (noun)
someone who asks a question	someone who asks a question