WordNet sense 1 (a sentence of inquiry that asks for a reply):

interrogation, interrogative, interrogative sentence

WordNet sense 2 (an instance of questioning):

enquiry, inquiry, query

WordNet sense 3 (a formal proposal for action made to a deliberative assembly for discussion and vote):

motion

WordNet sense 4 (the subject matter at issue):

head

WordNet sense 5 (uncertainty about the truth or factuality of existence of something):

doubt, doubtfulness, dubiousness

WordNet sense 6 (place in doubt or express doubtful speculation):

wonder

WordNet sense 7 (challenge the accuracy, probity, or propriety of):

oppugn, call into question

WordNet sense 8 (conduct an interview in television, newspaper, and radio reporting):

interview

WordNet sense 9 (pose a series of questions to):

interrogate