sackcloth /ˈsækˌklɑːθ/ noun Learner's definition of SACKCLOTH
[noncount]
: rough cloth that is used for making sacks麻袋布
sackcloth and ashes
◊ To don/wear sackcloth and ashes means to publicly express or show sorrow or regret for having done something wrong.(对所做的错事公开)忏悔,表示痛心