Subtile

Definition:

(a.) Thin; not dense or gross; rare; as, subtile air; subtile vapor; a subtile medium.
(a.) Delicately constituted or constructed; nice; fine; delicate; tenuous; finely woven.
(a.) Acute; piercing; searching.
(a.) Characterized by nicety of discrimination; discerning; delicate; refined; subtle.
(a.) Sly; artful; cunning; crafty; subtle; as, a subtile person; a subtile adversary; a subtile scheme.

Compare subtile with other words:

substile vs. subtile