Remorse

n.	1.	The anguish, like gnawing pain, excited by a sense of guilt; compunction of conscience for a crime committed, or for the sins of one's past life.
	2.	Sympathetic sorrow; pity; compassion. Curse on the unpardoning prince, whom tears can draw To no remorse. - Dryden. But evermore it seem'd an easier thing At once without remorse to strike her dead. - Tennyson.

Noun

1.

remorse - a feeling of deep regret (usually for some misdeed) Synonyms: compunction, self-reproach

anxiety, apologies, attrition, ayenbite of inwit, bitterness, contriteness, embarrassment, grief, guilt, guilty conscience, humiliation, mortification, pangs of conscience, penance, penitence, penitently, regretfulness, regrets, regretting, remorse of conscience, remorsefulness, repentance, repining, rue, ruefulness, self-reproach, shame, shamefacedness, shamefastness, shamefulness, sorriness, wistfulness, woe