Sackcloth n. : Linen or cotton cloth such as sacks are made of; coarse cloth; anciently, a cloth or garment worn in mourning, distress, mortification, or penitence.

Example:
How many Americans will be in "mourning & lamenting" while wearing "Sackcloth & ashes" on this INAUGURATION?

Taxonomy
hairshirt, cilice, Opus, sackcloth and ashes, penance, free encyclopedia, repentance, hair, cilicium, discomfort, atonement, animal hair, Woe, religious orders, the Catholic Church, coarse cloth, Etymology, history.

Defination from the web:
sackcloth) and ashes as a sign of repentance and atonement. Jesus expected people to repent using sackcloth and ashes: "Woe to you, Korazin! Woe to you, Bethsaida! ...