D defs.my
Entry 1 sense Webster, 1913

passerby

/păs'-ẽrb-ē/ · pas·ser·by · IPA /pˈæsərbiː/
01 n. One who passes by, especially casually or by chance; one not directly involved in some action; a passer.
  1. 1.
    One who passes by, especially casually or by chance; one not directly involved in some action; a passer.