'inadvertently' originates from Latin, specifically the word 'inadvertentem,' where 'in-' meant 'not' and 'advertentem' meant 'turning the mind to.' 'Dismissed' comes from Latin 'dimittere,' where 'dis-' meant 'apart' and 'mittere' meant 'send.'

'inadvertentem' transformed into the French word 'inadvertent,' and eventually became the modern English word 'inadvertently.' 'Dimittere' transformed into the Old French word 'desmettre,' and eventually became the modern English word 'dismiss.'

Initially, 'inadvertently' meant 'not turning the mind to,' but over time it evolved into its current meaning of 'unintentionally.' 'Dismiss' initially meant 'send away,' and this meaning has largely remained the same in modern usage.