sackcloth and ashes

from WordNet (r) 3.0 (2006)

sackcloth and ashes
    n 1: a display of extreme remorse or repentance or grief

from Moby Thesaurus II by Grady Ward, 1.0

27 Moby Thesaurus words for "sackcloth and ashes":
      Day of Atonement, Yom Kippur, asceticism, black,
      cold purgatorial fires, crape, cypress, cypress lawn,
      deep mourning, fasting, flagellation, hair shirt, lustration,
      maceration, mortification, mourning, mourning band, penance,
      penitence, penitential act, penitential exercise, purgation,
      purgatory, repentance, sackcloth, weeds, yew