'intentionally' originates from Latin, specifically the word 'intentio,' where 'in-' meant 'toward' and 'tendere' meant 'to stretch.' 'Decrease' originates from Latin, specifically the word 'decrescere,' where 'de-' meant 'down' and 'crescere' meant 'to grow.'

'intention' transformed into the Old French word 'intencion,' and eventually became the modern English word 'intention.' 'Decrescere' transformed into the Old French word 'decreistre,' and eventually became the modern English word 'decrease.'

Initially, 'intention' meant 'a stretching toward something,' but over time it evolved into its current meaning of 'purpose or aim.' 'Decrease' initially meant 'to grow less,' and this meaning has largely remained the same in modern usage.