The Collaborative International Dictionary of English v.0.48:

Jackal \Jack"al`\, n. [Pers. shagh[=a]l: cf. OF. jackal, F.
   chacal; cf. Skr. [,c][.r]g[=a]la.]
   [1913 Webster]
   1. (Zool.) Any one of several species of carnivorous animals
      inhabiting Africa and Asia, related to the dog and wolf.
      They are cowardly, nocturnal, and gregarious. They feed
      largely on carrion, and are noted for their piercing and
      dismal howling.
      [1913 Webster]

   Note: The common species of Southern Asia (Canis aureus) is
         yellowish gray, varied with brown on the shoulders,
         haunches, and legs. The common African species (Canis
         anthus) is darker in color.
         [1913 Webster]

   2. One who does mean work for another's advantage, as jackals
      were once thought to kill game which lions appropriated.
      [Colloq.] --Ld. Lytton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

jackal
    n 1: Old World nocturnal canine mammal closely related to the
         dog; smaller than a wolf; sometimes hunts in a pack but
         usually singly or as a member of a pair [syn: jackal,
         Canis aureus]

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "jackal":
   African hunting dog, Cape hunting dog, adherent, apple-polisher,
   ass-licker, backscratcher, backslapper, bootlick, bootlicker,
   brown-nose, brownie, brush wolf, clawback, courtier, coyote,
   creature, cringer, dingo, disciple, dummy, dupe, fawner,
   figurehead, flatterer, flunky, follower, footlicker, fox, gillie,
   goon, groveler, handshaker, hanger-on, helot, henchman, hyena,
   instrument, kowtower, lackey, led captain, lickspit, lickspittle,
   lobo, man, mealymouth, medicine wolf, minion, myrmidon, peon,
   prairie wolf, puppet, reynard, satellite, serf, slave, spaniel,
   stooge, suck, sycophant, thug, timber wolf, timeserver, toad,
   toady, tool, truckler, tufthunter, votary, wolf, yes-man