subtility

noun

1. (countable, obsolete, uncountable)Cunning, craftiness.

   “—L. By thus glorying in their resistance to the vice of Nature's law—if, indeed, anything natural be vicious—they become not only like inhuman and cruel beasts, but even like the devils whose pride and subtility they borrow.”

2. (countable, obsolete, uncountable)A cunning scheme; a trick, a con.

   “And that such their subtility might not be perceived, they made him a like paire of eares and nose of wax: wherfore you may see that the poore miser for lucre of a little mony sustained losse of his members.”

   “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.”

3. (countable, uncountable)Excessive refinement of argument; casuistry.
4. (countable, uncountable)A convoluted or refined argument.

   “There is no subtilitie so vaine, but confounds me.”

5. (countable, uncountable)Fineness; subtlety.

   “As we rise in the scale of forces towards greater subtility, the forces become more important and efficient.”