(n.) One who inquires or examines; questioner; investigator.

Paul Pry Peeping Tom asker auditor autodidact busybody catechist cross-interrogator cross-questioner detective eavesdropper educatee examiner gossip inquisitionist inquisitive inquisitor interlocutor interpellator interrogator interrogatrix interviewer learner monitor nosy Parker opinion-sampler poller pollster praepostor prefect prober pry pupil querier querist questioner questionist quidnunc quizzer rubberneck rubbernecker sampler scholar scopophiliac secret agent self-taught person sightseer snoop snooper student studier trainee voyeur yenta