大穴

Meanings

1. Noun

   large hole
2. big deficit; heavy losses
3. long-shot win (in horse racing, etc.); big winnings (on a long shot); a killing (made from a bet)

• 仮かりに競馬けいばでたまたま大穴おおあなを当あてたとしましょう。

  Let's suppose you happen to strike it rich at the races.