Gaff/ɡæf/ Definition 1 of 3Pro Tip 1/3Fishing Equipment Gaff is specifically used in fishing to land a catch and not for fishing in general. The angler reached for his gaff as the marlin neared the boat. Pro Tip 2/3Not a Weapon Despite having a hook or spear, a gaff is not meant for combat or hunting. He bought a gaff for fishing trips, not for self-defense. Pro Tip 3/3Large Fish A gaff is particularly helpful for large or heavy fish that can't be lifted with a line. For the deep-sea trophy fish, you'll need a sturdy gaff.