1. The quality or state of being subtile; thinness; fineness; as, the subtility of air or light.
2. Refinement; extreme acuteness; subtlety. Intelligible discourses are spoiled by too much subtility in nice divisions. (locke)
3. Cunning; skill; craft. To learn a lewd man this subtility. (Chaucer)
4. Slyness in design; artifice; guile; a cunning design or artifice; a trick; subtlety. O full of all subtility and all mischief. (acts xiii. 10)
In senses 2, 3, and 4 the word is more commonly written subtlety.
Origin: Contr. Fr. Subtility.