You can lose a game, or lose some money. You can even have loose change in your pocket. Just don't muddle their spellings up!
Lose: to fail at, or to be unable to find. "Ann would always lose her keys."
Loose: not tight or fixed in place. "The railings were really loose, a danger to everyone."
Learn the difference between these by this comparison:
The last two sound the same, the first two don't.