passer-by

剑桥词典

someone who is going past a particular place , especially when something unusual happens
（尤指在不寻常之事发生时经过某处的）过路人，行人
The gunmen opened fire , killing a policeman and a passer-by. 持枪者开枪打死了一名警察和一位路人。 返回 passer-by