adj. 1 a without one's mental faculties; unconscious. b (of the extremities etc.) numb; without feeling. 2 (usu. foll. by of, to) unaware; indifferent (insensible of her needs). 3 without emotion; callous. 4 too small or gradual to be perceived; inappreciable. insensibly adv.
[ ME f. OF insensible or L insensibilis (as IN-(1), SENSIBLE) ]