Disconcert

DISCONCERT, v.t. [dis and concert.]
1. To break or interrupt any order, plan or harmonious scheme; to defeat; to frustrate. The emperor disconcerted the plans of his enemy. Their schemes were disconcerted.
2. To unsettle the mind; to discompose; to disturb; to confuse. An unexpected question may disconcert the ablest advocate in his argument.

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