Onlooker/ˈɑːnlʊkər/ Definition 1 of 1Pro Tip 1/3Passive Role An onlooker usually observes an event without influencing it directly. As the argument escalated, I remained an onlooker, not wanting to get involved. Pro Tip 2/3Not Involved 'Onlooker' implies no responsibility or participation in the ongoing situation. The onlookers at the parade simply watched the floats go by. Pro Tip 3/3Physical Presence Onlookers are usually physically present at the location of the event. Onlookers at the scene of the accident provided details to the police.