Adjective
subtil (comparative more subtil, superlative most subtil)
Obsolete form of subtle; sly, artful, cunning
I commend the Judge that seems fine and ingenious, so it tend to right and equity. And I condemn them, that either out of pleasure to shew a subtil wit will destroy, or out of incuriousness or negligence will not labour to support the act of the party by the art or act of the law. Sir Henry Hobart, 1st Baronet