(n.) The act of turning around an improper behavior; sorrow for what one has done; especially, contrition for sin\.

Day of Atonement Yom Kippur abject apology apology asceticism attrition change of heart cold purgatorial fires compunction contriteness contrition deathbed repentance fasting flagellation hair shirt heartfelt apology lustration maceration mea culpa mortification penance penitence penitential act penitential exercise penitently purgation purgatory reformation remorse rue ruth sackcloth and ashes saeta wearing a hairshirt