The Collaborative International Dictionary of English v.0.48:

Reptile \Rep"tile\ (r?p"t?l;277), a. [F. reptile, L. reptilis,
   fr. repere, reptum, to creep; cf. Lith. reploti; perh. akin
   to L. serpere. Cf. Serpent.]
   1. Creeping; moving on the belly, or by means of small and
      short legs.
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   2. Hence: Groveling; low; vulgar; as, a reptile race or crew;
      reptile vices.
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            There is also a false, reptile prudence, the result
            not of caution, but of fear.          --Burke.
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            And dislodge their reptile souls
            From the bodies and forms of men.     --Coleridge.
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The Collaborative International Dictionary of English v.0.48:

Reptile \Rep"tile\, n.
   1. (Zool.) An animal that crawls, or moves on its belly, as
      snakes,, or by means of small, short legs, as lizards, and
      the like.
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            An inadvertent step may crush the snail
            That crawls at evening in the public path;
            But he that has humanity, forewarned,
            Will tread aside, and let the reptile live.
                                                  --Cowper.
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   2. (Zool.) One of the Reptilia, or one of the Amphibia.
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   Note: The amphibians were formerly classed with Reptilia, and
         are still popularly called reptiles, though much more
         closely allied to the fishes.
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   3. A groveling or very mean person.
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WordNet (r) 3.0 (2006):

reptile
    n 1: any cold-blooded vertebrate of the class Reptilia including
         tortoises, turtles, snakes, lizards, alligators,
         crocodiles, and extinct forms [syn: reptile, reptilian]

Moby Thesaurus II by Grady Ward, 1.0:

129 Moby Thesaurus words for "reptile":
   Gila monster, Reptilia, agama, alligator, amphibian, anguine,
   animal, anole, aquatic, atiptoe, batrachian, bearded lizard, beast,
   biped, blindworm, box turtle, butterfly agama, canine, cannibal,
   carnivore, cayman, chameleon, clawback, colubriform, cosmopolite,
   crawling, creature, creeping, crocodile, crocodilian, cur,
   diamondback, dinosaur, dog, dragon, false map turtle, feline,
   flying dragon, froggy, gator, gavial, gecko, girdle-tailed lizard,
   glass snake, gnawer, green turtle, groveler, hawksbill,
   hawksbill turtle, herbivore, hound, hyena, iguana, insect,
   insectivore, invertebrate, leatherback, lickspittle, lizard,
   lizardlike, mammal, mammalian, marsupial, marsupialian, matamata,
   minion, mongrel, monitor, mugger, omnivore, on all fours,
   on tippytoe, on tiptoe, ophidian, pig, polecat, primate, quadruped,
   repent, reptant, reptatorial, reptilelike, reptilian, reptiliform,
   reptiloid, rodent, ruminant, saurian, scavenger, sea turtle,
   serpent, serpentiform, serpentile, serpentine, serpentlike,
   serpentoid, skunk, slithering, snake, snakelike, snaky,
   soft-shelled turtle, stump tail, swine, teju, terrapin, tippytoe,
   tiptoe, tiptoeing, toad, toadeater, toadish, toady, tortoise,
   tuatara, turtle, ungulate, varmint, vermin, vertebrate, viper,
   viperiform, viperish, viperlike, viperoid, viperous, vipery, whelp,
   worm