"Giant wave" refers to an enormous and powerful wave that can cause significant damage to the shorelines it hits. Some synonyms for the term include "monstrous wave," "colossal wave," "massive wave," "towering wave," and "enormous wave." Other words that convey the scale and intensity of a "giant wave" are "tsunami," "tidal wave," "seismic wave," and "rogue wave." These waves are often caused by natural phenomena like earthquakes, strong winds, or landslides. It's important to take precautions and stay clear of shorelines during such events to ensure safety.