The Collaborative International Dictionary of English v.0.48:

Lose \Lose\ (l[=oo]z), v. t. [imp. & p. p. Lost (l[o^]st; 115)
   p. pr. & vb. n. Losing (l[=oo]z"[i^]ng).] [OE. losien to
   loose, be lost, lose, AS. losian to become loose; akin to OE.
   leosen to lose, p. p. loren, lorn, AS. le['i]san, p. p. loren
   (in comp.), D. verliezen, G. verlieren, Dan. forlise, Sw.
   f["o]rlisa, f["o]rlora, Goth. fraliusan, also to E. loose, a
   & v., L. luere to loose, Gr. ly`ein, Skr. l[=u] to cut.
   [root]127. Cf. Analysis, Palsy, Solve, Forlorn,
   Leasing, Loose, Loss.]
   [1913 Webster]
   1. To part with unintentionally or unwillingly, as by
      accident, misfortune, negligence, penalty, forfeit, etc.;
      to be deprived of; as, to lose money from one's purse or
      pocket, or in business or gaming; to lose an arm or a leg
      by amputation; to lose men in battle.
      [1913 Webster]

            Fair Venus wept the sad disaster
            Of having lost her favorite dove.     --Prior.
      [1913 Webster]

   2. To cease to have; to possess no longer; to suffer
      diminution of; as, to lose one's relish for anything; to
      lose one's health.
      [1913 Webster]

            If the salt hath lost his savor, wherewith shall it
            be salted?                            --Matt. v. 13.
      [1913 Webster]

   3. Not to employ; to employ ineffectually; to throw away; to
      waste; to squander; as, to lose a day; to lose the
      benefits of instruction.
      [1913 Webster]

            The unhappy have but hours, and these they lose.
                                                  --Dryden.
      [1913 Webster]

   4. To wander from; to miss, so as not to be able to and; to
      go astray from; as, to lose one's way.
      [1913 Webster]

            He hath lost his fellows.             --Shak
      [1913 Webster]

   5. To ruin; to destroy; as destroy; as, the ship was lost on
      the ledge.
      [1913 Webster]

            The woman that deliberates is lost.   --Addison.
      [1913 Webster]

   6. To be deprived of the view of; to cease to see or know the
      whereabouts of; as, he lost his companion in the crowd.
      [1913 Webster]

            Like following life thro' creatures you dissect,
            You lose it in the moment you detect. --Pope.
      [1913 Webster]

   7. To fail to obtain or enjoy; to fail to gain or win; hence,
      to fail to catch with the mind or senses; to miss; as, I
      lost a part of what he said.
      [1913 Webster]

            He shall in no wise lose his reward.  --Matt. x. 42.
      [1913 Webster]

            I fought the battle bravely which I lost,
            And lost it but to Macedonians.       --Dryden.
      [1913 Webster]

   8. To cause to part with; to deprive of. [R.]
      [1913 Webster]

            How should you go about to lose him a wife he loves
            with so much passion?                 --Sir W.
                                                  Temple.
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   9. To prevent from gaining or obtaining.
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            O false heart! thou hadst almost betrayed me to
            eternal flames, and lost me this glory. --Baxter.
      [1913 Webster]

   To lose ground, to fall behind; to suffer gradual loss or
      disadvantage.

   To lose heart, to lose courage; to become timid. "The
      mutineers lost heart." --Macaulay.

   To lose one's head, to be thrown off one's balance; to lose
      the use of one's good sense or judgment, through fear,
      anger, or other emotion.
      [1913 Webster]

            In the excitement of such a discovery, many scholars
            lost their heads.                     --Whitney.

   To lose one's self.
      (a) To forget or mistake the bearing of surrounding
          objects; as, to lose one's self in a great city.
      (b) To have the perceptive and rational power temporarily
          suspended; as, we lose ourselves in sleep.

   To lose sight of.
      (a) To cease to see; as, to lose sight of the land.
      (b) To overlook; to forget; to fail to perceive; as, he
          lost sight of the issue.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Losing \Lo"sing\, a. [See Losenger.]
   Given to flattery or deceit; flattering; cozening. [Obs.]
   [1913 Webster]

         Amongst the many simoniacal that swarmed in the land,
         Herbert, Bishop of Thetford, must not be forgotten;
         nick-named Losing, that is, the Flatterer. --Fuller.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Losing \Los"ing\, a. [See Lose, v. t.]
   Causing or likely to cause a loss; as, a losing game or
   business; a losing strategy.
   [1913 Webster]

         Who strive to sit out losing hands are lost. --Herbert.
   [1913 Webster]

The Jargon File (version 4.4.7, 29 Dec 2003):

losing
 adj.

    Said of anything that is or causes a lose or lossage. ?The compiler is
    losing badly when I try to use templates.?


The Free On-line Dictionary of Computing (30 December 2018):

losing

    Said of anything that is or causes a lose or
   lossage.

   [Jargon File]