lost (adj.)

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.

Definitions of lost
lost (adj.)
deeply absorbed in thought;
lost in thought
Synonyms: bemused / preoccupied
lost (adj.)
no longer in your possession or control; unable to be found or recovered;
a lost child
his lost book
lost opportunities
lost friends
lost (adj.)
having lost your bearings; confused as to time or place or personal identity;
Synonyms: confused / disoriented
lost (adj.)
spiritually or physically doomed or destroyed;
the lost platoon
lost souls
a lost ship
a lost generation
lost (adj.)
not gained or won;
a lost prize
a lost battle
lost (adj.)
incapable of being recovered or regained;
his lost honor
lost (adj.)
not caught with the senses or the mind;
words lost in the din
Synonyms: missed
lost (adj.)
perplexed by many conflicting situations or statements; filled with bewilderment;
she felt lost on the first day of school
Synonyms: baffled / befuddled / bemused / bewildered / confounded / confused / mazed / mixed-up / at sea
lost (adj.)
unable to function; without help;
Synonyms: helpless
lost (n.)
people who are destined to die soon;
Synonyms: doomed