verb (used with object)
- to disturb the self-possession of; perturb; ruffle: Her angry reply disconcerted me completely.
- to throw into disorder or confusion; disarrange: He changed his mind and disconcerted everybody’s plans.
- to disturb the composure of
- to frustrate or upset
1680s, from Middle French disconcerter (Modern French déconcerter) “confused,” from dis- “do the opposite of” (see dis-) + concerter (see concert). Related: Disconcerted; disconcerting; disconcertingly.