unperceiving

c.1300, via Anglo-French parceif, Old North French *perceivre (Old French perçoivre) "perceive, notice, see; recognize, understand," from Latin percipere "obtain, gather, seize entirely, take possession of," also, figuratively, "to grasp with the mind, learn, comprehend," literally "to take entirely," from per "thoroughly" (see per) + capere "to grasp, take" (see capable).

Replaced Old English ongietan. Both the Latin senses were in Old French, though the primary sense of Modern French percevoir is literal, "to receive, collect" (rents, taxes, etc.), while English uses the word almost always in the metaphorical sense. Related: Perceived; perceiving.