c. 1400, "lacking the power to feel with the senses," from Latin insensibilis "that cannot be felt," from in- "not" (see in- (1)) + sensibilis (see sensible). Also sometimes in Middle English "incapable of being felt or perceived by the senses" (early 15c.). Meaning "unconscious" is attested from early 15c. See insensate.[insensible etymology, insensible origin, 英语词源]