What does "subtilty" mean?

Subtilty: Refinement; extreme acuteness; subtlety. Intelligible discourses are spoiled by too much subtility in nice divisions. Locke.

Additional senses

  1. 2.Cunning; skill; craft. [Obs.] To learn a lewd man this subtility. Chaucer.
  2. 3.Slyness in design; artifice; guile; a cunning design or artifice; a trick; subtlety. O full of all subtility and all mischief. Acts xiii.
  3. 4.Note: In senses 2, 3, and 4 the word is more commonly written subtlety.

Sources