Hack
A "hack" is a form of cheating that exploits some aspect of the game to grant a user an unfair advantage. Hacks differ from exploits in that hacks are almost never achieved in-game, but usually require an external technique; often a third party program.
The term is in common use and can be combined with the another word to detail what it's doing. Players might refer to a way too cheat a character as a "a charhack," and the "maphack" program is notoriously common on Diablo 2's Battle.net.
Word Usage
"Hack" can be used as a verb, to describe the process of cheating.
- "I hacked his character."
Or as a noun, to describe the program or technique itself.
- "I used a hack to steal his gold."