Lose definition: to come to be without (something in one's possession or care), through accident, theft, etc., so that there is little or no prospect of recovery.. See examples of LOSE used in a sentence. ' Lose ' is a verb referring to the act of no longer possessing or misplacing something, while ' loose ' is an adjective describing something that is not tight or firmly attached. Learn the meaning of lose as a verb in English, with synonyms, antonyms, idioms, and phrasal verbs. Find out how to use lose in different contexts, such as losing money, time, jobs, or control. Learn the meaning, pronunciation, and examples of the verb lose , which means to be unsuccessful in retaining possession of something or to suffer deprivation. Compare lose with loose and find related words and phrases.