1. Also called black quarter, symptomatic anthrax. Veterinary Pathology. an infectious, often fatal disease of cattle and sheep, caused by the soil bacterium Clostridium chauvoei and characterized by painful, gaseous swellings in the muscles, usually of the upper parts of the legs.
  2. Plant Pathology.
    1. a disease of cabbage and other cruciferous plants, characterized by dry, black lesions on the base of the stem, caused by a fungus, Phoma lingam.
    2. a disease of potatoes, characterized by wet, black lesions on the base of the stem, caused by a bacterium, Erwinia atroseptica.
  3. a swindler, especially in racing or gambling.
  4. British Informal. a strikebreaker; scab.
verb (used with object), black·legged, black·leg·ging. British Informal.
  1. to replace (a worker) who is on strike.
  2. to refuse to support (a union, union workers, or a strike).
  3. to betray or deceive (a person or cause).
verb (used without object), black·legged, black·leg·ging.
  1. British Informal. to return to work before a strike is settled.

Origin of blackleg

1715–25; black + leg; orig. of nonliteral senses unclear; cf. jackleg Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for blackleg

Historical Examples of blackleg

  • Most of these seemed as eager for the race as an English blackleg for the Derby.

    The Quadroon

    Mayne Reid

  • Knave he was,—cheat at cards, blackleg on the turf,—but forgery!

  • He already knows his rival to be a blackguard; in all likelihood he is also a blackleg.

  • I released the blackleg, and he sat helpless in his chair, and glared at us.

    Great Porter Square, v. 2

    Benjamin Leopold Farjeon

  • Could I think of treading in the boots of a blackleg, albeit they never were his own?

British Dictionary definitions for blackleg


  1. Also called: scab British
    1. a person who acts against the interests of a trade union, as by continuing to work during a strike or taking over a striker's job
    2. (as modifier)blackleg labour
  2. Also called: black quarter an acute infectious disease of cattle, sheep, and pigs, characterized by gas-filled swellings, esp on the legs, caused by Clostridium bacteria
  3. plant pathol
    1. a fungal disease of cabbages and related plants caused by Phoma lingam, characterized by blackening and decay of the lower stems
    2. a similar disease of potatoes, caused by bacteria
  4. a person who cheats in gambling, esp at cards or in racing
verb -legs, -legging or -legged
  1. British to act against the interests of a trade union, esp by refusing to join a strike
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for blackleg

"swindler," especially in equestrian events, 1771, from black (adj.) + leg (n.), but the exact signification is uncertain.

Online Etymology Dictionary, © 2010 Douglas Harper