The centripetal acceleration is the acceleration a body experiences in centripetal motion (moving in a circle or along an arc). Centripetal acceleration always points towards the centre of the circle, hence the direction of the moving body is constantly changing (since its velocity is always tangent to the circle). On the other hand, the centrifugal force is a fictitious (imaginary) force the object experiences during circular motion. The direction of this force is opposite to the direction of the centripetal acceleration. The best example to visualise this difference is to imagine being in a car. If the car takes a sharp left turn, the passengers experience a thrust towards the right (the centrifugal force), whereas the friction between the road and the tyres results in the centripetal acceleration allowing the turn to take place.