Synonyms:
bystander
Meaning: a nonparticipant spectator
Usage examples
As an impartial bystander
"Is this your rug, captain?" asked a bystander just as we were driving off.
If so, it would be a chase worth following--a diversion rendered the more exquisite to Lanyard by the spice of novelty, since for once he would figure as a dispassionate bystander.
When two dogs are fighting, any bystander may attempt to separate them with impunity. The brutes are so anxious to tear each other that they have no energies left for other purposes.