scab

noun

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

• 2mange or a similar skin disease in animals.
• [usually with modifier] 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 dislike and disgust.
• derogatory a person who refuses to strike or to join a labor union or who takes over the job responsibilities of a striking worker.

verb (scabs, scabbing, scabbed)

• 1 (usually as adjective scabbed) become encrusted or covered with a scab or scabs:she rested her scabbed fingers on his arm

• 2act or work as a scab.