Question

give clear definition of centripetal force

Answer 1

A force which act on a body  moving in a circular path and is directed towards centre around which the body is moving.

Answer 2

Centripetal means radially inward towards the center of the curved path. In circular motion centripetal force is responsible for keeping a body in a circular path.

Example: In a thread-stone system, the stone is no allowed to fly off tangentially because the thread holds it in the circular path.