Source : Webster's Revised Unabridged Dictionary (1913)

Passer \Pass"er\, n.
   One who passes; a passenger.

Source : WordNet®

passer
     n 1: a person who passes by casually or by chance [syn: {passerby},
           {passer-by}]
     2: a person who passes as a member of a different ethnic or
        racial group
     3: a student who passes and examination
     4: (football) a ball carrier who tries to gain ground by
        throwing a forward pass [syn: {forward passer}]
     5: type genus of the Passeridae [syn: {genus Passer}]