If opposing Pokémon know any move also known by the user, they are prevented from using it.
As long as the user remains in battle, opponents cannot use any move which is also known by the user (including Pokémon switched in after the move was used). If the user's moveset changes while Imprison is in effect (such as by Mimic, Sketch, Transform, or learning a new move by leveling up), opponents are prevented from using the new moves.
On the turn that Imprison is used, if an opposing Pokémon would move after Imprison is used and it selected a move the user knows that turn, it will be unable to use that move and make no action that turn (i.e. PP for that move is not consumed). If a Pokémon has no moves with PP other than moves prevented by Imprison, it will Struggle.
Imprison will fail if no opponent possesses a move the user knows at the time Imprison is used.
Imprison cannot be passed by Baton Pass.