lost / lôst; läst/ • past and past participle of lose.• adj. 1. unable to find one's way; not knowing one's whereabouts: Help! We're lost! they got lost in the fog. ∎  unable to be found: he turned up with my lost golf clubs. ∎  (of a person) very confused or insecure or in great difficulties: she stood there clutching a drink, feeling completely lost I'd be lost without her.2. denoting something that has been taken away or cannot be recovered: if only one could recapture one's lost youth! ∎  (of time or an opportunity) not used advantageously; wasted: the decision meant a lost opportunity to create 200 jobs. ∎  having perished or been destroyed: a memorial to the lost crewmen.3. (of a game or contest) in which a defeat has been sustained: the lost election of 1994.PHRASES: all is not lost used to suggest that there is still some chance of success or recovery.be lost for words be so surprised, confused, or upset that one cannot think what to say.be lost on fail to influence or be noticed or appreciated by (someone): the significance of his remarks was not lost on Scott.be lost to be no longer affected by or accessible to: once a vital member of the community, he is now lost to the world.get lost [often in imper.] inf. go away (used as an expression of anger or impatience): Why don't you leave me alone? Go on, get lost!give someone up for lost stop expecting that a missing person will be found alive.make up for lost time do something faster or more often in order to compensate for not having done it quickly or often enough before.