'resentful' originates from the French word 'ressentir,' where 're-' meant 'again' and 'sentir' meant 'to feel.'

'ressentir' transformed into the English word 'resent' and eventually became the modern English word 'resentful.'

Initially, it meant 'to feel again,' but over time it evolved into its current meaning of 'feeling bitterness or indignation.'