Source : Webster's Revised Unabridged Dictionary (1913)

Tripper \Trip"per\, n.
   1. One who trips or supplants; also, one who walks or trips
      nimbly; a dancer.

   2. An excursionist.

Source : WordNet®

tripper
     n 1: (slang) someone who has taken a psychedelic drug and is
          undergoing hallucinations
     2: a walker or runner who trips and almost falls [syn: {stumbler}]
     3: a tourist who is visiting sights of interest [syn: {sightseer},
         {excursionist}, {rubberneck}]
     4: a catch mechanism that acts as a switch; "the pressure
        activates the tripper and releases the water" [syn: {trip}]