scab

American  

[skab] / skæb /

noun

1. the incrustation that forms over a sore or wound during healing.

2. Veterinary Pathology. a mangy disease in animals, especially sheep; scabies.

3. Plant Pathology.

   1. a disease of plants characterized by crustlike lesions on the affected parts and caused by a fungus or bacterium.

   2. one of these crustlike lesions.

4. a worker who refuses to join a labor union or to participate in a union strike, who takes a striking worker's place on the job, or the like.

5. Slang. a rascal or scoundrel.

6. Metallurgy.

   1. a projection or roughness on an ingot or casting from a defective mold.

   2. a surface defect on an iron or steel piece resulting from the rolling in of scale.

7. Carpentry. a short, flat piece of wood used for various purposes, as binding two timbers butted together or strengthening a timber at a weak spot.

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verb (used without object)

scabbed, scabbing

1. to become covered with a scab.

2. to act or work as a scab.

scab British  

/ skæb /

noun

1. the dried crusty surface of a healing skin wound or sore

2. a contagious disease of sheep, a form of mange, caused by a mite ( Psoroptes communis )

3. a fungal disease of plants characterized by crusty spots on the fruits, leaves, etc

4. derogatory

   1. Also called: blackleg.  a person who refuses to support a trade union's actions, esp one who replaces a worker who is on strike

   2. ( as modifier )

      scab labour

5. a despicable person

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verb

1. to become covered with a scab

2. (of a road surface) to become loose so that potholes develop

3. to replace a striking worker

scab Scientific  

/ skăb /

1. A crust that forms over a healing wound, consisting of dried blood, plasma, and other secretions.

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scab Cultural  

1. Informally, a worker who stays on the job while others go on strike. Also, a worker brought in to keep a plant operating when its work force is on strike. (See strikebreaker.)

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Other Word Forms

• scablike adjective

Etymology

Origin of scab

1200–50; 1800–10 scab for def. 4; Middle English < Old Norse skabb scab, itch; shabby, shave

Explanation

Kids who fall and skin their knees know what a scab is: it's the crusty patch of skin that forms when a scrape or cut is healing. A wound will form a scab as it heals, whether it's a cut or a burn. Skin has an amazing ability to repair itself, and a scab is evidence of this. Scab is also a slang term for someone who crosses a picket line during a strike, choosing to work instead of joining coworkers in protesting low wages or harsh treatment by an employer. This kind of scab first meant "unpleasant person" in the late 1500s.

Example Sentences

“These people believe that you take the scab off of a wound and take it off again and again until something miraculous happens,” Boritt grumbles to the camera.

From The Wall Street Journal • Feb. 12, 2026

Apples are also among the most heavily treated fruits, with pesticides used in particular to fight apple scab, the main fungal threat to orchards.

From Barron's • Jan. 29, 2026

The show says it doesn’t plan to scab.

From Los Angeles Times • Mar. 5, 2024

But a series of challenges - from the onslaught of fungal scab, the impact of climate change, and a range of economic hurdles - has thrown the flourishing industry into a state of crisis.

From BBC • Dec. 6, 2023

Hatchet flicked the last of his scab into the dirt and squinted at the raw skin beneath.

From "The Reader" by Traci Chee

Related Words

• blister
• crater
• defect
• discoloration
• disfigurement
• flaw
• wound