Source : Webster's Revised Unabridged Dictionary (1913)

Blackleg \Black"leg`\, n.
   1. A notorious gambler. [Colloq.]

   2. A disease among calves and sheep, characterized by a
      settling of gelatinous matter in the legs, and sometimes
      in the neck. [Eng.]

Source : WordNet®

blackleg
     n : someone who works (or provides workers) during a strike
         [syn: {scab}, {strikebreaker}, {rat}]
     v : take the place of work of someone on strike [syn: {scab}, {rat}]
     [also: {blacklegging}, {blacklegged}]