sackcloth
noun [ U ] uk/ˈsæk.klɒθ/ us/ˈsæk.klɑːθ/ (also sacking)
粗麻布，麻袋布
the thick, rough material used to make sacks (= large strong bags)
Idiom
wear sackcloth and ashesidiom 极其懊悔，处于忏悔中
to show by your behaviour that you are very sorry for something you did that was wrong