From Longman Dictionary of Contemporary Englishsackclothsack‧cloth /ˈsæk-klɒθ $ -klɒːθ/ (also sacking /ˈsækɪŋ/) noun [uncountable] 1 TIMrough cloth used for making sacks2 → wear sackcloth and ashes
Examples from the Corpus
sackcloth• Hearing the man, Dara stripped off his sackcloth cloak and threw it down.• In ten seconds or so I would be either triumphant or in sackcloth and ashes.• She had chosen for herself the human equivalent of sackcloth and ashes, and she denounced herself for a masochist.• I have no wish to see Aitken go through the rest of his life wearing sackcloth and ashes. 