The Collaborative International Dictionary of English v.0.48:

Lizard \Liz"ard\, n. [OE. lesarde, OF. lesarde, F. l['e]zard, L.
   lacerta, lacertus. Cf. Alligator, Lacerta.]
   [1913 Webster]
   1. (Zool.) Any one of the numerous species of reptiles
      belonging to the order Lacertilia; sometimes, also
      applied to reptiles of other orders, as the Hatteria.
      [1913 Webster]

   Note: Most lizards have an elongated body, with four legs,
         and a long tail; but there are some without legs, and
         some with a short, thick tail. Most have scales, but
         some are naked; most have eyelids, but some do not. The
         tongue is varied in form and structure. In some it is
         forked, in others, as the chameleons, club-shaped, and
         very extensible. See Amphisb[ae]na, Chameleon,
         Gecko, Gila monster, Horned toad, Iguana, and
         Dragon, 6.
         [1913 Webster]

   2. (Naut.) A piece of rope with thimble or block spliced into
      one or both of the ends. --R. H. Dana, Ir.
      [1913 Webster]

   3. A piece of timber with a forked end, used in dragging a
      heavy stone, a log, or the like, from a field.
      [1913 Webster]

   Lizard snake (Zool.), the garter snake (Eut[ae]nia
      sirtalis).

   Lizard stone (Min.), a kind of serpentine from near Lizard
      Point, Cornwall, England, -- used for ornamental purposes.
      [1913 Webster] lizardfish

WordNet (r) 3.0 (2006):

lizard
    n 1: relatively long-bodied reptile with usually two pairs of
         legs and a tapering tail
    2: a man who idles about in the lounges of hotels and bars in
       search of women who would support him [syn: lounge lizard,
       lizard]

Easton's 1897 Bible Dictionary:

Lizard
   Only in Lev. 11:30, as rendering of Hebrew _letaah_, so called
   from its "hiding." Supposed to be the Lacerta gecko or fan-foot
   lizard, from the toes of which poison exudes. (See CHAMELEON.)