An exploit is a case in video games where two or more separate mechanics individually work as intended but, when combined, yield an effect that is not meant to occur. Exploits are different from glitches, which occur due to programming oversights affecting a singular process. That said, there can be some grey area between what defines a glitch and an exploit.
Exploits in the Super Smash Bros. series have been rare. Thus far, these exploits have seen use in tournaments, where they are generally considered legal.