Question

how can we differentiate between a chameleon and a lizard?​

Answer 1

As nouns the difference between lizard and chameleon is that lizard is any reptile of the order squamata, usually having four legs, external ear openings, movable eyelids and a long slender body and tail while chameleon is 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.

As a adjective chameleon is describing something that changes color.