'disconcert' originates from French, specifically the word 'déconcerter,' where 'dé-' meant 'apart' and 'concerter' meant 'to bring together.'

'déconcerter' transformed into the English word 'disconcert,' and eventually became the modern English word 'disconcertingly.'

Initially, it meant 'to disturb the composure of,' and this meaning has largely remained the same in modern usage.