SUB'TILTY, noun [Latin subtilitas.] 1. Thinness; fineness; exility; in a physical sense; as the subtilty of air or light; the subtilty of sounds. 2. Refinement; extreme acuteness. Intelligible discourses are spoiled by too much subtilty in nice divisions. 3. Slyness in design; cunning; artifice; usually but less properly written subtlety.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI