blackleg
Preserved but no longer current.
A rascal, swindler, or card cheat. The derivation of this term was solemnly argued before the full Court of Queen’s Bench upon a motion for a new trial for libel, but was not decided by the learned tribunal. Probably it is from the custom of sporting and turf men wearing black top-boots. Hence BLACKLEG came to be the phrase for a professional sporting man, and thence for a professional sporting cheat. The word is now in its worst sense diminished to "leg."
Era: ca. 1874 (Victorian)
Sources & notes
Historical definition reproduced from Hotten’s The Slang Dictionary (1874, public domain; Project Gutenberg #42108, retrieved 2026-07-31). Reflects the attitudes of its era.
Common questions
What does “blackleg” mean?
A rascal, swindler, or card cheat. The derivation of this term was solemnly argued before the full Court of Queen’s Bench upon a motion for a new trial for libel, but was not decided by the learned tribunal. Probably it is from the custom of sporting and turf men wearing black top-boots. Hence BLACKLEG came to be the phrase for a professional sporting man, and thence for a professional sporting cheat. The word is now in its worst sense diminished to "leg."
Is “blackleg” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.