"judge erroneously or wrongfully, form a wrong opinion," early 15c., misjugen, from mis- (1) "badly, wrongly" + judge (v.). Related: Misjudged; misjudging.

late 14c., "to count erroneously," also "to misjudge, deceive oneself," from Old French mesconter "give a false statement; miscalculate, be wrong in reckoning" (Modern French mécompter), from mes- "badly, wrongly" (see mis- (2)) + conter (see count (v.)). Related: Miscounted; miscounting.