Synonyms of onlooker

2 Syllables
gazer, gawkers, viewers, witness, standee, clapper, watcher, viewer, sightseer, gawker, clappers, gazers
3 Syllables
witnesses, stander-by, beholders, observer, perceivers, observers, attestant, looker-on, testifier, bystanders, spectators, beholder, passer-by, attendee, bystander, perceiver, eyewitness, spectator, testifiers
4 Syllables
rubbernecker, eyewitnesses
5 Syllables
corroborator, corroborators