'unrepentance' originates from the prefix 'un-' meaning 'not' and the word 'repentance,' which comes from the Latin 'paenitentia,' meaning 'regret or remorse.'

'repentance' evolved from the Old French word 'repentir,' which was derived from the Latin 'paenitere,' eventually forming the modern English word 'repentance.' The prefix 'un-' was added to denote the opposite meaning.

Initially, 'repentance' meant 'feeling regret for sins or wrongdoings,' and 'unrepentance' has consistently meant the lack of such feelings.