Source : Webster's Revised Unabridged Dictionary (1913)

Handicap \Hand"i*cap\, n. [From hand in cap; -- perh. in
   reference to an old mode of setting a bargain by taking
   pieces of money from a cap.]
   1. An allowance of a certain amount of time or distance in
      starting, granted in a race to the competitor possessing
      inferior advantages; or an additional weight or other
      hindrance imposed upon the one possessing superior
      advantages, in order to equalize, as much as possible, the
      chances of success; as, the handicap was five seconds, or
      ten pounds, and the like.

   2. A race, for horses or men, or any contest of agility,
      strength, or skill, in which there is an allowance of
      time, distance, weight, or other advantage, to equalize
      the chances of the competitors.

   3. An old game at cards. [Obs.] --Pepys.

Handicap \Hand"i*cap\, v. t. [imp. & p. p. {Handicapped}; p. pr.
   & vb. n. {Handicapping}.]
   To encumber with a handicap in any contest; hence, in
   general, to place at disadvantage; as, the candidate was
   heavily handicapped.

Source : WordNet®

handicap
     n 1: the condition of being unable to perform as a consequence of
          physical or mental unfitness; "reading disability";
          "hearing impairment" [syn: {disability}, {disablement},
          {impairment}]
     2: advantage given to a competitor to equalize chances of
        winning
     3: something immaterial that interferes with or delays action
        or progress [syn: {hindrance}, {deterrent}, {impediment},
        {balk}, {baulk}, {check}]
     [also: {handicapping}, {handicapped}]

handicap
     v 1: injure permanently; "He was disabled in a car accident"
          [syn: {disable}, {invalid}, {incapacitate}]
     2: attempt to forecast the winner (especially in a horse race)
        and assign odds for or against a contestant
     3: put at a disadvantage; "The brace I have to wear is
        hindering my movements" [syn: {hinder}, {hamper}]
     [also: {handicapping}, {handicapped}]