Cheat can mean many things, both as a verb and a noun:

• In relationships, to cheat is to have an affair
• To take advantage of a situation, in real life or otherwise. Specific methods include:
  • Cheating (general methods)
  • Cheating in poker
  • Cheating in online games
• A cheat is a person who lies or engages in any of the above.
• A cheat code is a hidden means of gaining an unfair advantage in a computer game.
• A cheat is someone who defects in a Prisoner's Dilemma situation
• Cheat is an alternative name for the card game Bullshit
• "The Cheat" is a character in Homestar Runner.
• The Cheat is an early and honored American film.
• There is also a Cheat River and Cheat Lake in the Appalachian Mountains (in the United States).