Decoy is a tactic where you force a piece to a square that it doesn't want to be on. This can be used to remove a defender, lure a piece into a fork or even lure a king into checkmate.
White hopes to trade bishops in a desperate situation, trying to find chances to draw. Can you decoy White's rook to a square where it will be lost to a fork?
White's rook is decoyed to a forking square - win the rook!
Black ends up winning a rook and a bishop for a rook and this endgame is won.