1. thin, tenuous, or rarefied, as a fluid or an odor.
2.fine or delicate in meaning or intent; difficult to perceive or understand
3. delicate or faint and mysterious
4. requiring mental acuteness, penetration, or discernment
5.characterized by mental acuteness or penetration
6. cunning, wily, or crafty
7. insidious in operation
8. skillful, clever, or ingenious