Disconcert, v. t. [imp. & p. p. Disconcerted; p. pr. & vb. n. Disconcerting.]
Etymology: [Pref. dis- + concert: cf. OF. desconcerter, F. déconcerter.]
1. To break up the harmonious progress of; to throw into disorder or confusion; as, the emperor disconcerted the plans of his enemy.
2. To confuse the faculties of; to disturb the composure of; to discompose; to abash. The embrace disconcerted the daughter-in-law somewhat, as the caresses of old gentlemen unshorn and perfumed with tobacco might well do. Thackeray.
Syn. -- To discompose; derange; ruffle; confuse; disturb; defeat; frustrate.
1 other Webster entry under this spelling
Disconcert, n.
Want of concert; disagreement. Sir W. Temple.
Shades of meaning
Fernald has no entry of its own for disconcert; he lists it under abash.
He lists it without comment; the entries above explain its neighbors.