The Collaborative International Dictionary of English v.0.48:

Puncher \Punch"er\, n.
   One who, or that which, punches.
   [1913 Webster]

WordNet (r) 3.0 (2006):

puncher
    n 1: a hired hand who tends cattle and performs other duties on
         horseback [syn: cowboy, cowpuncher, puncher,
         cowman, cattleman, cowpoke, cowhand, cowherd]
    2: someone who delivers punches
    3: a tool for making holes or indentations [syn: punch,
       puncher]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "puncher":
   broncobuster, buckaroo, caballero, cattleman, cavalier, cavalryman,
   chevalier, circus rider, cowboy, cowgirl, cowhand, cowherd, cowman,
   cowpuncher, drover, equestrian, equestrienne, gaucho, goatherd,
   gooseboy, gooseherd, herder, herdsman, hogherd, horse soldier,
   horse wrangler, horseback rider, horsebacker, horseherd, horseman,
   horsewoman, jockey, knight, mounted policeman, pigman, postboy,
   postilion, rider, roughrider, sheepherder, sheepman, shepherd,
   shepherdess, steeplechaser, swanherd, swineherd, trick rider,
   vaquero, waddy, wrangler