Scab

n. 1 crust over a healing cut, sore, etc. 2 (often attrib.) colloq. derog. blackleg. 3 skin disease, esp. in animals. 4 fungous plant disease. v. (bb) 1 col. log. derog. act as a blackleg. 2 form a scab, heal over. o scabby adj. (ier, iest). [Old Norse: cf. SHABBY] scabbard isk bad/ n. hist. sheath of a sword etc. [AngloFrench]