Subtle /(?)/

Sub·tle

Subtle

a.
  1. Sly in design; artful; cunning; insinuating; subtile; -- applied to persons; as, a subtle foe.
  2. Cunningly devised; crafty; treacherous; as, a subtle stratagem.
  3. Characterized by refinement and niceness in drawing distinctions; nicely discriminating; -- said of persons; as, a subtle logician; refined; tenuous; sinuous; insinuating; hence, penetrative or pervasive; -- said of the mind; its faculties, or its operations; as, a subtle intellect; a subtle imagination; a subtle process of thought; also, difficult of apprehension; elusive.
    Things remote from use, obscure and subtle.
  4. Smooth and deceptive. [Obs.]
    Like to a bowl upon a subtle ground [bowling ground].