What is the definition of random and simple harmonic motion ?

Random Motion: Random motion is a motion in which the particle moves in a zig-zag manner and not in a straight line. It is a type of motion that is unpredictable. In this type of motion, the object moves in any direction, and the direction continually changes.

Simple Harmonic Motion: Simple harmonic motion, in physics, repetitive movement back and forth through an equilibrium, or central, position, so that the maximum displacement on one side of this position is equal to the maximum displacement on the other side.