'penitent' originates from Latin, specifically the word 'paenitens,' where 'paenitēre' meant 'to repent.'

'paenitens' transformed into the Old French word 'penitent,' and eventually became the modern English word 'penitent' through Middle English.

Initially, it meant 'to feel regret or sorrow for sins,' and this meaning has largely remained the same in modern usage.