subtility

noun5

1. •
   Fineness; subtlety.

   • As we rise in the scale of forces towards greater subtility, the forces become more important and efficient. — 1916
2. •
   Excessive refinement of argument; casuistry.
3. •
   A convoluted or refined argument.

   • There is no subtilitie so vaine, but confounds me. — 1603
4. •
   (no longer used) Cunning, craftiness.
5. •
   (no longer used) A cunning scheme; a trick, a con.

   • I cannot omit a subtility of one of those quack operators, with which he gulled the poor people to crowd about him, but did nothing for them without money. — 1665