Source : Webster's Revised Unabridged Dictionary (1913)

Lost \Lost\, a. [Prop. p. p. of OE. losien. See {Lose}, v. t.]
   1. Parted with unwillingly or unintentionally; not to be
      found; missing; as, a lost book or sheep.

   2. Parted with; no longer held or possessed; as, a lost limb;
      lost honor.

   3. Not employed or enjoyed; thrown away; employed
      ineffectually; wasted; squandered; as, a lost day; a lost
      opportunity or benefit.

   5. Having wandered from, or unable to find, the way;
      bewildered; perplexed; as, a child lost in the woods; a
      stranger lost in London.

   6. Ruined or destroyed, either physically or morally; past
      help or hope; as, a ship lost at sea; a woman lost to
      virtue; a lost soul.

   7. Hardened beyond sensibility or recovery; alienated;
      insensible; as, lost to shame; lost to all sense of honor.

   8. Not perceptible to the senses; no longer visible; as, an
      island lost in a fog; a person lost in a crowd.

   9. Occupied with, or under the influence of, something, so as
      to be insensible of external things; as, to be lost in
      thought.

   {Lost motion} (Mach.), the difference between the motion of a
      driver and that of a follower, due to the yielding of
      parts or looseness of joints.