chameleon

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various tropical Old World lizards of the family Chamaeleonidae, characterized by their ability to change color.
2. n. See anole.
3. n. A changeable or inconstant person: "In his testimony, the nominee came off as . . . a chameleon of legal philosophy” ( Joseph A. Califano, Jr.)

Century Dictionary and Cyclopedia

1. n. A lizard-like reptile of the family Chamæleontidæ, having a naked body, a prehensile tail, feet suited for grasping branches, and the eye covered by a single circular eyelid with an aperture in the center. There are about 59 species, of which the bestknown is Chamæleon vulgaris, a native of Africa, extending into Asia and the south of Europe. Its body is 6 or 7 inches long, and the tail 5 inches. The skin is cold to the touch, and contains small grains or eminences which are of a bluish-gray color in the shade, but in the light of the sun all parts of the body become of a grayish-brown or tawny color. The extraordinary faculty which the chameleon possesses of changing its color, in accordance with that of the objects by which it is surrounded or with its temper when disturbed, is due to the presence of clear or pigment-bearing contractile cells placed at various depths in the skin, their contractions and dilatations being under the control of the nervous system. Its power of fasting and habit of inflating itself gave rise to the fable that it lives on air. It is in reality insectivorous, its tongue, which is long and covered with a viscid saliva, being darted at its prey and securing it when touched.
2. n. In the southern United States and West Indies, a true lizard of the family Anolididæ or Iguanidæ. Also chamæleo.
3. n. [capitalized] A constellation invented by Bayer, situated beneath the feet of the Centaur.
4. n. Same as chamæleon, 3.

Wiktionary

1. n. A small to mid-size reptile, of the family Chamaeleonidae, and one of the best known lizard families able to change color and project its long tongue.
2. n. A person with inconstant behavior; one able to quickly adjust to new circumstances.
3. adj. Describing something that changes color.

GNU Webster's 1913

1. n. A lizardlike reptile of the genus Chamæleo, of several species, found in Africa, Asia, and Europe. The skin is covered with fine granulations; it has eyes which can move separately, the tail is prehensile, and the body is much compressed laterally, giving it a high back. It is remarkable for its ability to change the color of its skin to blend with its surroundings.
2. n. a person who changes opinions, ideas, or behavior to suit the prevailing social climate; an opportunist.

WordNet 3.0

1. n. lizard of Africa and Madagascar able to change skin color and having a projectile tongue
2. n. a faint constellation in the polar region of the southern hemisphere near Apus and Mensa
3. n. a changeable or inconstant person