Onlookers (10)
(Other definitions for spectators that I've seen before include "Those watching" , "Witnesses" , "Viewers" .)
'onlookers' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for bystanders that I've seen before include "Those happening to be present" , "Onlookers" , "Spectators" , "Observers" .)