Im`per*cep"ti*ble (?), a. [Pref. im- not + perceptible: cf. F. imperceptible.]
Not perceptible; not to be apprehended or cognized by the souses; not discernible by the mind; not easily apprehended.
Almost imperceptible to the touch.
Its operation is slow, and in some cases almost imperceptible.
-- Im`per*cep"ti*ble*ness, n. -- Im`per*cep"ti*bly, adv.
Their . . . subility and imperceptibleness.
Sir M. Hale.
© Webster 1913.