Akademik

disconcert
v.tr.
1 disturb the composure of; agitate; fluster (disconcerted by his expression).
2 spoil or upset (plans etc.).
Derivatives:
disconcertedly adv. disconcerting adj. disconcertingly adv. disconcertion n. disconcertment n.
Etymology: obs. F desconcerter (as DIS-, CONCERT)

Useful english dictionary. 2012.