Sandbagging
The term sandbagging describes purposefully doing badly or failing a task to reduce expectations and then, when it counts, doing the best you can do to exceed any expectations. For example, in computer gaming, a player may purposefully lose at games to make the computer believe they're not as good as they are. Then, when the player's level is lowered, and they're competing against easier players, they play their best to get a sense of domination. In games where betting is involved, a person may sandbag others into thinking they're not very good so they can win when a high-stakes bet is made.
Is sandbagging cheating?
Yes. In all games and competitions, sandbagging is a form of cheating because you're giving yourself an unfair advantage. Players caught sandbagging may be disqualified from competitions or banned from competing in future competitions.