a person standing near but not taking part in an event or activity
person who watches
a person who watches something happening without taking part
person observing an event
a person looking at (a sport, game, show etc)
person who watches event
a person watching a television programme
witness
a person who was actually present at an event and should, for this reason, be able to describe it; a person who gives evidence under oath in a law court
person who observes an event