adj. (subtler, subtlest) 1 evasive or mysterious; hard to grasp (subtle charm; a subtle distinction). 2 (of scent, colour, etc.) faint, delicate, elusive (subtle perfume). 3 a capable of making fine distinctions; perceptive; acute (subtle intellect; subtle senses). b ingenious; elaborate; clever (a subtle device). 4 archaic crafty, cunning. subtleness n. subtly adv.
[ ME f. OF sotil f. L subtilis ]