Which wave behavior results from two waves colliding and the temporary combined wave results in a smaller wave than the original waves?

When two waves (either mechanical or electromagnetic) combine in such a way that their peaks and troughs combine to produce a wave of large amplitude, the wave behaviour is known as constructive interference. The opposite process is where the peaks of one wave combines with the troughs of another wave in order to produce a wave of smaller amplitude. This process is known as destructive interference.