noun
remorse
rih-MORS/rɪˈmɔːrs/
Deep regret or guilt for something wrong one has done.
His remorse shows as he offers the broken keepsake back with an apology.

Etymology
Remorse carries the image of a “biting back.” The expression “biting of conscience” connects that image to the inward pain of recognizing one's own wrongdoing.
In context
he never ever expressed remorse, regret, doubted his his actions, asked himself whether what he has done was somehow wrong.
More examples
- She felt deep remorse for the lie.
- The letter expressed genuine remorse.
- He showed little remorse after the discovery.
Forms
remorse
Similar words
- regret
- May concern any unwanted outcome, not necessarily one's own wrongdoing.
- contrition
- Contrition especially suggests repentance for wrongdoing.