Question

give one example of a situation in which velocity of a body is in opposite direction of its acceleration

Answer 1

throwing a ball vertically upward as when we throw the ball upward acceleration increase but velocity decreases

Answer 2

 Yes, a body can have acceleration and velocity in opposite directions.
Examples:   

A body thrown upwards vertically. (gravity is then acting in the opposite direction)
A body in simple harmonic motion. (Displacement is in the opposite direction to the acceleration)
.A stretched rubber band (the elastic force is opposite to the motion of the vibration) or a person on a swing.