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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"
adj.
capable of being perceived by the senses or the mind; especially capable of being handled or touched or felt; "a barely palpable dust"; "felt sudden anger in a palpable wave"; "the air was warm and close--palpable as cotton"
adj.
being or occurring in fact or actuality; having verified existence; not illusory; "real objects"; "real people; not ghosts"; "a film based on real life"; "a real illness"; "real humility"; "Life is real! Life is earnest!"- Longfellow