The act of committing all of your efforts to stopping a particular rival from winning a competitive game/event once you realise you have no way of winning yourself.
Game of monopoly: 3 players left
"John you will give me all of your properties for only $500". "Yeh Jimmy sure, as long as you let me go around the board 3 times without having to pay rent". Cheeky smirk to the Bryn. John i'l give you $5000 for all of your properties and allow you not to pay rent on my properties for 3 turns. "Nah Bryn thats fine, i'm going to stick with Jimmy's deal".
As a result Bryn is quickly knocked out of the game, after which John immediately insults Bryn about how bad he is at the game, forfeits to Jimmy and enjoys the glory of his spite-victory.