The Collaborative International Dictionary of English v.0.48:

Drover \Dro"ver\, n.
   1. One who drives cattle or sheep to market; one who makes it
      his business to purchase cattle, and drive them to market.
      [1913 Webster]

            Why, that's spoken like an honest drover; so they
            sell bullocks.                        --Shak.
      [1913 Webster]

   2. A boat driven by the tide. [Obs.] --Spenser.
      [1913 Webster]

WordNet (r) 3.0 (2006):

drover
    n 1: someone who drives a herd [syn: herder, herdsman,
         drover]

Moby Thesaurus II by Grady Ward, 1.0:

49 Moby Thesaurus words for "drover":
   Gyropilot, automatic pilot, boatheader, boatsteerer, cattleman,
   cicerone, courier, cowboy, cowgirl, cowhand, cowherd, cowman,
   cowpuncher, coxswain, dragoman, gaucho, goatherd, gooseboy,
   gooseherd, guide, guidepost, guider, helmsman, herd, herder,
   herdsman, hogherd, horse wrangler, horseherd, mercury, navigator,
   pigman, pilot, pointer, puncher, river pilot, sheepherder,
   sheepman, shepherd, shepherdess, steerer, steersman, swanherd,
   swineherd, tour director, tour guide, vaquero, waddy, wrangler