presumption (n.)
mid-13c., "seizure and occupation without right," also "taking upon oneself more than is warranted," from Old French presumcion (12c., Modern French présomption) and directly from Late Latin praesumptionem (nominative praesumptio) "confidence, audacity," in classical Latin, "a taking for granted, anticipation," noun of action from past participle stem of praesumere "to take beforehand," from prae "before" (see pre-) + sumere "to take" (see exempt (adj.)). In English, the meaning "the taking of something for granted" is attested from c.1300. Presumptuous preserves the older sense.