lose, loose

To lose something is to be deprived of it. It also means to suffer defeat. It's a verb. Loose is most commonly used as an adjective or adverb. It means free, unbound, lax. If you're making fun of someone, you call them a loser, not a looser.

Cobra may lose many battles, but it hasn't lost the war against G.I. Joe.

Many people unable to solve the Rubik's Cube pry the pieces loose and put them back together in the correct order.