"wrong action, a failure on the part of authority," 1425, from Anglo-Fr. mesprisioun "mistake, error, wrong action or speech," from O.Fr. mespris, pp. of mesprendre "to mistake, act wrongly," from mes- "wrongly" (see mis- (2)) + prendre "take," from L. prendere, contracted from prehendere "seize" (see prehensile). In 16c., misprision of treason was used for lesser degrees of guilt (those not subject to capital punishment), esp. for knowing of treasonable actions or plots but not informing the authorities. This led to the common supposition in legal writers that the word means "failure to denounce" a crime.