An answerer answers a question.
A defendant (or their lawyer) tries to defend themselves against a criminal charge in court.
A respondent (or their lawyer) responds to a motion in court.
As CopperKettle suggests, a replier replies to a statement or question.
A torture victim is someone who has been "put to the question" by the inquisition.
A witness is someone who testifies in court. They may be subject to examination and cross-examination by the lawyers, and answer the lawyers' questions.
An invitee RSVPs. (Répondez s'il vous plaît is French for "Respond if it pleases you.")
An interviewee answers a series of questions. Policemen ask questions of subjects, suspects, witnesses, and persons of interest. Employers interview job applicants. Journalists also conduct interviews. Talk show hosts interview guests and callers.
There are many words, which emphasize different meaning. Some are negative.
Pleasure aspect of doing whatever you want: bon vivant, hedonist, pleasure seeker.
Going wherever you want, possibly new places (metaphorically too): globetrotter, explorer, pioneer.
Free thought, defiance: maverick, liberal, free thinker, nonconformist.
Disregard for traditional social structures: bohemian, hippie, beatnik.
Disregard for manner and social grace: boor, barbarian, brute, philistine.
Ambition: doer, achiever.
Disregard for law: criminal, outlaw, gangster, robber, lawbreaker, desperado, etc.
Acting in self-interest without regard for trust: back-stabber, snitch, cheater, two-timer.
Acting in self-interest without regard for others: egoist, narcissist.
Best Answer
Inviter is someone that invites.
Generally, the thing that instigates the action will have an -er ending, and the thing that is in receipt will have -ee ending.