Definitions:

1. A coarse, rough fabric, traditionally made from goat hair, flax, or hemp, used for making sacks or bags, and historically also worn as a symbol of mourning, repentance, or humility, especially in biblical and religious contexts. NOUN
   • The prophet wore sackcloth to mourn the fall of the city.
2. A course, heavy-duty fabric originally used for bags and sacks, but also worn in ancient times as sign of grief or penitence. NOUN
   • Sackcloth was uncomfortable, emphasizing the wearer's grief or guilt.
3. A garment made of coarse sacking, formerly worn as an indication of remorse. NOUN
   • The ascetic donned coarse sackcloth as a symbol of humility and penitence.

Synonyms:

• ascetic vestiment
• burlap
• hessian
• penitential garment
• sacking