scab

Concise Oxford English Dictionary © 2008 Oxford University Press:
scab/skab/

▶noun

• 1 a dry, rough protective crust that forms over a cut or wound during healing.

• 2 mange or a similar skin disease in animals.

  ■ any of a number of fungal diseases of plants in which rough patches develop, especially on apples and potatoes.

• 3 informal a person or thing regarded with contempt.

  ■ a person who refuses to strike or who takes the place of a striking worker.

▶verb (scabs, scabbing, scabbed)

• 1 (usu. as adj. scabbed) become encrusted with a scab or scabs.

• 2 act or work as a scab.

  ■ Brit. informal scrounge.

– derivatives
scabbiness noun,
scabby adjective.

– origin ME: from ON skabb; rel. to dial. shab (cf. shabby).