Source : Webster's Revised Unabridged Dictionary (1913)

Looper \Loop"er\, n.
   1. An instrument, as a bodkin, for forming a loop in yarn, a
      cord, etc.

   2. (Zo["o]l.) The larva of any species of geometrid moths.
      See {Geometrid}.

Source : WordNet®

looper
     n : small hairless caterpillar having legs on only its front and
         rear segments; mostly larvae of moths of the family
         Geometridae [syn: {measuring worm}, {inchworm}]