lost (adj.) Look up lost at Dictionary.com
c. 1300; "wasted, ruined, spent in vain," c. 1500; also "no longer to be found, gone astray" (1520s), past participle adjectives from lose. Meaning "spiritually ruined, inaccessible to good influence" is from 1640s. Related: Lostness.

Of battles, games, etc. in which one has been defeated, 1724; hence Lost Cause in reference to the bid for independence by the southern states of the U.S., first as the title of the 1866 pro-Southern history of the CSA and the rebellion written by Virginia journalist E.A. Pollard (1832-1872). Lost Generation in reference to the youth that came of age when World War I broke is first attested 1926 in Hemingway's "The Sun Also Rises," where he credits it to Gertrude Stein. Lost-and-found as the name of a department where misplaced articles are brought or sought is by 1907.