bystander
n.
1610s, from by + agent noun from stand, v.. They have been innocent at least since 1829. Stander-by is from 1540s.
〔李〕[by-=near by 附近；stand v.站立；-er n.=aperson…者⇒“a person who stands near by 站在附近者”→] n. person who stands near but does not take part旁观者