1. To be unsuccessful in retaining possession of; mislay: He's always losing his car keys.
2.
a. To be deprived of (something one has had): lost her art collection in the fire; lost her job.
b. To be left alone or desolate because of the death of: lost his wife.
c. To be unable to keep alive: a doctor who has lost very few patients.
3. To be unable to keep control or allegiance of: lost his temper at the meeting; is losing supporters by changing his mind.
4. To fail to win; fail in: lost the game; lost the court case.
5. To fail to use or take advantage of: Don't lose a chance to improve your position.
6. To fail to hear, see, or understand: We lost the plane in the fog. I lost her when she started speaking about thermodynamics.
7.
a. To let (oneself) become unable to find the way.
b. To remove (oneself), as from everyday reality into a fantasy world.
8. To rid oneself of: lost five pounds.
9. To consume aimlessly; waste: lost a week in idle occupations.
10. To wander from or become ignorant of: lose one's way.
11.
a. To elude or outdistance: lost their pursuers.
b. To be outdistanced by: chased the thieves but lost them.
12. To become slow by (a specified amount of time). Used of a timepiece.
13. To cause or result in the loss of: Failure to reply to the advertisement lost her the job.
14. To cause to be destroyed. Usually used in the passive: Both planes were lost in the crash.
15. To cause to be damned.
v.intr.
1. To suffer loss: investors who lost heavily on the firm's stock.
2. To be defeated: Our team lost in overtime.
3. To operate or run slow. Used of a timepiece.