double or nothing

A wager that can be used in any sort of competition, wherein the winner would receive twice the prize or nothing. Hyphenated when used as an adjective. Come on, one more match, double or nothing! If you win, you don't have to pay. I beat my brother at billiards for the second time in our double-or-nothing game. Now he owes me $100 instead of $50! It was double or nothing, that's why I walked away—I didn't want to risk losing the prize I'd already won!

double or nothing

a gamble to decide whether a loss or debt should be doubled or cancelled.

A British variant of double or nothing is double or quits .