sackcloth (n.)youdaoicibaDictYouDict[sackcloth 词源字典]
penitential or grieving garb, late 13c., literally "cloth of which sacks are made," from sack (n.1) + cloth. In the Biblical sense it was of goats' or camels' hair, the coarsest possible clothing.[sackcloth etymology, sackcloth origin, 英语词源]