sackcloth

noun

both clergy and laity wore an extremely uncomfortable black sackcloth:

hessian, sacking, hopsack, hopsacking, burlap;

North American, & Indian gunny;

in the East Indies tāt;

historical poldavy, stramin, sugarsack.

□ in sackcloth and ashes (also wearing sackcloth and ashes)

penitent, contrite, regretful, full of regret, sorrowful, rueful, remorseful, apologetic, conscience-stricken, ashamed, guilt-ridden, chastened, shamefaced, self-reproachful, guilty;

rare compunctious.

▷antonyms unrepentant.