1. Unable to find one's way: a lost child. 2. a. No longer in the possession, care, or control
of someone or something: a lost pen. b. No longer in existence; vanished or spent: lost
youth. c. No longer known or practiced: a lost art. d. Beyond reach, communication, or influence:
The expedition was lost to the world for two months. 3. Not used to one's benefit or advantage:
a lost opportunity. 4. Having not been or unlikely to be won; unsuccessful: a
lost battle; a lost cause. 5. Beyond recovery or redemption; fallen or destroyed: a lost
soul. 6. a. Completely involved or absorbed; rapt: lost in thought. b. Bewildered or confused