remorseful Definition

remorse
noun

1. A feeling of bitter regret for wrong one has done.

Thesaurus: regret, sorrow, anguish, guilt, bad conscience, repentance, ruefulness, penitence, contrition, grief, compunction, self-reproach.
2. Compassion or pity.

Derivative: remorseful
adj

Feeling or showing bitter regret for wrong one has done
Thesaurus: sorry, regretful, conscience-stricken, guilt-ridden, guilty, ashamed, rueful, sad, sorrowful, apologetic, penitent, repentant, contrite, compunctious; Antonym: impenitent, remorseless.

Derivative: remorsefully
adverb

Derivative: remorsefulness
noun

Derivative: remorseless

Feeling or showing no guilt or concern at one's own wrongdoing.
Thesaurus: cruel, callous, harsh, relentless, ruthless, tyrannical, merciless, pitiless, exacting, inflexible, implacable, inexorable; Antonym: merciful, repentant.

Without respite; relentless.

Derivative: remorselessly
adverb

Derivative: remorselessness
noun

Etymology: 14c: from French remors, from Latin remordere, remorsum to vex, from mordere to bite or sting.