- impalpable (adj.)
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- c. 1500, "too unsubstantial to be perceived by touch," from French impalpable or directly from Medieval Latin impalpabilis, from assimilated form of in- "not, opposite of" (see in- (1)) + palpabilis (see palpable). Figurative (mental) sense of "that cannot be grasped by the intellect" is from 1774. Related: Impalpably; impalpability.