- thin, tenuous, or rarefied, as a fluid or an odor.
- fine or delicate in meaning or intent; difficult to perceive or understand: subtle irony.
- delicate or faint and mysterious: a subtle smile.
- requiring mental acuteness, penetration, or discernment: a subtle philosophy.
- characterized by mental acuteness or penetration: a subtle understanding.
- cunning, wily, or crafty: a subtle liar.
- insidious in operation: subtle poison.
- skillful, clever, or ingenious: a subtle painter.