Synonyms of the word

listener

• n. Someone who listens, especially to a speech or a broadcast.
• n. (computing, programming, chiefly Java) A function that runs in response to an event; an event handler.

attender

• n. An attendee; one who attends a course, meeting etc.
• n. (metaphysics) The subject; one who experiences.

auditor

• n. One who audits bookkeeping accounts.
• n. In many jurisdictions, an elected or appointed public official in charge of the public accounts; a comptroller.
• n. One who audits an academic course; who attends the lectures but does not earn academic credit.
• n. (rare) One who listens, typically as a member of an audience.
• n. (Scientology) One trained to perform spiritual guidance procedures.

beholder

• n. Someone who observes or beholds; an observer or spectator.
• n. (fantasy) A fictional monster in roleplaying games, a floating orb of flesh with a large mouth and many…

hearer

• n. (dated) One who hears; a devout listener.

observer

• n. One who makes observations, monitors or takes notice.
• n. One who adheres or follows laws, guidelines, etc.
• n. A person sent as a representative, to a meeting or other function to monitor but not to participate.
• n. A country or other entity which has limited participation rights within an organization.
• n. (military) A crew member on an aircraft who makes observations of enemy positions or aircraft.
• n. (military) A sentry etc. manning an observation post.

perceiver

• n. Agent noun of perceive; one who perceives.

percipient

• adj. Having the ability to perceive, especially to perceive quickly.
• adj. (psychology, education, dated) Perceiving events only in the moment, without reflection, as a very young…
• n. (philosophy, psychology) One who perceives something.
• n. (parapsychology) One who has perceived a paranormal event.