Dictionary.com
Thesaurus.com

blackleg

American  
[blak-leg] / ˈblækˌlɛg /

noun

  1. Also called black quarter.  Also called symptomatic anthraxVeterinary 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)

British Informal.
blacklegged, blacklegging
  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)

blacklegged, blacklegging
  1. British Informal. to return to work before a strike is settled.

blackleg British  
/ ˈblæklɛɡ /

noun

  1. Also called: scab

    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

"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

verb

  1. 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

Etymology

Origin of blackleg

First recorded in 1715–25; black + leg; the origin of nonliteral senses is unclear; cf. jackleg

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Phil Burbank is based on Savage’s step-uncle, eccentric William “Bill” Brenner, who died of blackleg just as Phil dies of anthrax.

From Washington Post Feb. 15, 2022

And then all the conversations, while the blackleg spread to cow and bison.

From Nature Nov. 13, 2018

His first film as producer was The Angry Silence, an anti-trades union tract, in which Attenborough was a blackleg and yet a hero.

From The Guardian Aug. 24, 2014

Or they can be plants with virus or blackleg, or plants that are not "true-to-type", meaning they have the wrong morphology and are therefore too tall or deformed in another way, he adds.

From BBC Jun. 20, 2012

"You wouldn't 'ave me a blackleg, Lizzie, would you?" he asked.

From Mrs. Bindle Some Incidents from the Domestic Life of the Bindles by Jenkins, Hebert

Western blacklegged ticks are migrating into Southern California from the northern part of the state.

From Los Angeles Times Aug. 18, 2025

Overall, the blacklegged tick population has been expanding for at least four decades, researchers say.

From Seattle Times May 17, 2024

But when deer disappear, the blacklegged ticks dwindle, said Professor Fish.

From New York Times Jun. 29, 2023

For example, deer and rodent habitats are increasingly overlapping with human communities—and all three species are hosts for the blacklegged tick, also aptly named the deer tick.

From Scientific American Jun. 14, 2023

"I wad see that they blacklegged nae mair."

From The Underworld The Story of Robert Sinclair, Miner by Welsh, James C.

But that's blacklegging and I'd sooner starve than blackleg.

From The Workingman's Paradise An Australian Labour Novel by Miller, John Maurice

She smiled grimly to watch Mrs. Macanany and viragoes like her pouring oil on the flames and drumming the weak-kneed up and screaming against "blacklegging" as a thing accurst.

From The Workingman's Paradise An Australian Labour Novel by Miller, John Maurice

There was a strike on at some building and he went on as a laborer, blacklegging.

From The Workingman's Paradise An Australian Labour Novel by Miller, John Maurice

But you'll feel better in the end and your wife will be better right away and the children, and it won't be blacklegging on those who're trying to make things better.

From The Workingman's Paradise An Australian Labour Novel by Miller, John Maurice

Vocabulary.com logo
by dictionary.com

Dictionary.com's Learning Companion

Go beyond just looking up words.
Remember them forever with VocabTrainer.

Start training