Im·per·cep·ti·ble a. Not perceptible; not to be apprehended or cognized by the senses; not discernible by the mind; not easily apprehended.
Almost imperceptible to the touch. --Dryden.
Its operation is slow, and in some cases almost imperceptible. --Burke.
-- Im*per*cep*ti*ble*ness, n. -- Im*per*cep*ti*bly, adv.
Their . . . subtilty and imperceptibleness. --Sir M. Hale.
adj : impossible or difficult to perceive by the mind or senses;
"an imperceptible drop in temperature"; "an
imperceptible nod"; "color is unperceivable to the
touch" [syn: unperceivable] [ant: perceptible]