blackleg

UK: /ˈblæklɛg/ US: (blak′leg′)

Inflections of 'blackleg' (v): (⇒ conjugate)

blacklegs

v 3rd person singular

blacklegging

v pres p

blacklegged

v past

blacklegged

v past p

WordReference Random House Unabridged Dictionary of American English © 2026

black•leg  (blak′leg′), n., v., -legged, -leg•ging. 
n. 

1. Veterinary Diseases Also called black quarter, symptomatic anthrax. 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 Diseases
   • 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.
   • a disease of potatoes, characterized by wet, black lesions on the base of the stem, caused by a bacterium, Erwinia atroseptica.
3. a swindler, esp. in racing or gambling.
4. British Terms a strikebreaker;
   scab.

v.t. Brit. Informal. 

5. to replace (a worker) who is on strike.
6. to refuse to support (a union, union workers, or a strike).
7. to betray or deceive (a person or cause).

v.i. 

8. British Terms to return to work before a strike is settled.

• 1715–25; black + leg; origin, originally of nonliteral senses unclear; compare jackleg

Collins Concise English Dictionary © HarperCollins Publishers::

blackleg / ˈblæklɛɡ/ noun

1. Also called: scab 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

verb ( -legs, -legging, -legged)

1. to act against the interests of a trade union, esp by refusing to join a strike