Synonyms for Scab:

n.

black eye, abscess, blackhead, bedsore, boil, slough, athlete's foot. direct action, industrial action, apostate, general strike, go-slow, deserter, traitor, come out, grievance procedure, cooling-off period, go out on strike, action, collective bargaining, turncoat. •blemish (noun)
fleck, mark, eyesore, scratch, blister, spoilage, slit, scuff, blemish, notch, disfigurement, damage, fault, distortion, imperfection, sore, hack, score, brand, fracture, chip, rift, scar, defacement, splotch, flaw, dot, pockmark, blot, mar, tarnish, stain, spot, check, abrasion, speck, nick, lesion, wart, deformity, drawback, impurity, defect, freckle, scrape, blotch, kink, discoloration, hurt, weal, stigma, gash.
•fink (noun)
rat.
•scab (noun)
cicatrize, scab over, strikebreaker, cicatrise, blackleg, rat.
•scar (noun)
disfigurement, defect, flaw, pockmark, hurt, mark, discoloration.

v.

•flake (verb)
chip, blister.

Other synonyms:

•Other relevant words:
boil, cicatrize, scab over, apostate, strikebreaker, rat, blackleg, blackhead, traitor, abscess, cicatrise, deserter.

Usage examples for scab

1. The rich brown earth turned cleanly as the plow wounded it, and the scorching sun burned a healing scab over the wound. – The Lost Wagon by James Arthur Kjelgaard

2. Good land, I ain't no more of a scab than you be! – The Portion of Labor by Mary E. Wilkins Freeman