'gullibility' originates from the English word 'gullible,' which is derived from the verb 'gull,' meaning 'to deceive or trick.'

'gull' transformed from the Middle English word 'gullen,' which meant 'to swallow or devour,' and eventually became the modern English word 'gull' with the meaning 'to deceive.'

Initially, it meant 'to swallow or devour,' but over time it evolved into its current meaning of 'to deceive or trick.'