'fat' originates from Old English, specifically the word 'fǣtt,' where 'fǣtt' meant 'well-fed or plump.'

'fǣtt' transformed into the Middle English word 'fat,' and eventually became the modern English word 'fat.'

Initially, it meant 'well-fed or plump,' but over time it evolved into its current meaning of 'having a large amount of excess flesh.'