Definition of: subtle

(sut′l) adjective
1. Characterized by cunning, craft, or artifice; wily; crafty.
2. Keen; penetrative; discriminating; subtle humor; overrefined.
3. Apt; skilful.
4. Executed with nice art; ingenious; clever.
5. Insidious; secretly active.
6. Hard to understand; abstruse.
7. Of delicate texture.
8. Subtile. See synonyms under ACUTE, ASTUTE, FINE¹, INSIDIOUS, SUBTILE. [<OF soutil <L subtilis fine, orig. closely woven <sub- under + tela a web]
—sub′tle·ness noun
—sub′tly adverb