To be deprived of or cease to have something. She didn't want to lose her favorite necklace.
To fail to win a game, contest, or argument. The team worked hard but still managed to lose the match.
To misplace something temporarily. I often lose my keys in the house.
To suffer the loss of someone through death or separation. He was devastated to lose his best friend in the accident.
To fail to maintain or keep something, such as a job or position. She was worried she might lose her job after the company downsized.
To become unable to find one's way. We took a wrong turn and began to lose our way in the forest.
To fail to understand, follow, or keep in communication with someone or something. You lost me halfway through your explanation.
To undergo a reduction in weight, amount, or value. He hopes to lose ten pounds before summer.
(of a clock or watch) To run slow, indicating a time earlier than the correct time. This old clock loses about three minutes a week.