Sŭb'tle, a.

(sŭt'l), a. [compar. SUBTLER: superl. SUBTLEST.] [Contracted from subtile, q. v.]

1. Sly in design; artful; cunning; insinuating; subtle; — applied to persons; as, a subtle foe.
2. Cunningly devised; as, a subtle stratagem.
3. Made level or smooth by careful labor; even. [Obs. and rare.] “Like to a bowl upon a subtle ground [i. e., a bowling ground].” Shak.