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