/blak"leg'/ , n. , v. , blacklegged, blacklegging .
n.
1. Also called black quarter, symptomatic anthrax . Vet. Pathol. 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 Pathol.
a. 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.
b. 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. Brit. Informal. 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. Brit. Informal. to return to work before a strike is settled.
[ 1715-25; BLACK + LEG; orig. of nonliteral senses unclear; cf. JACKLEG ]