(n.) One who asks questions; an inquirer.

Paul Pry Peeping Tom asker busybody catechist cross-interrogator cross-questioner detective eavesdropper examiner gossip inquirer inquisitionist inquisitive inquisitor interlocutor interpellator interrogator interrogatrix interviewer nosy Parker opinion-sampler poller pollster prober pry querier querist questionist quidnunc quizzer rubberneck rubbernecker sampler scopophiliac secret agent sightseer snoop snooper voyeur yenta