'stressful' originates from the word 'stress,' which comes from Middle English 'stresse,' derived from Old French 'estresse,' meaning 'narrowness' or 'oppression.'

'stresse' transformed into the modern English word 'stress,' and the suffix '-ful' was added to form 'stressful.'

Initially, 'stress' referred to physical pressure or strain, but over time it evolved to include mental and emotional strain, leading to the adjective 'stressful.'