subtle /sutˈl/

1. Tenuous, slight
2. Elusive, impalpable
3. Showing or calling for fine discrimination
4. Delicate, refined
5. Overrefined or overrefining, rarefied
6. Abstruse
7. Crafty, artful
8. Insidious, devious
9. Ticklish, tricky (Shakespeare)

subtilīzāˈtion or subtilīsāˈtion /sut-/ noun

subtilize or subtilise /sutˈ/ transitive verb

1. To rarefy, refine
2. To make subtle

To refine, use subtlety

• cagouls
• cagy
• cagyness
• cagynesses
• cahier
• cahiers
• cahoot
• cahoots
• cahow
• cahows
• CAI
• caillach
• caille
• cailleach
• cailleachs
• cailles
• cailliach
• caimac
• caimacam
• caiman
• caimans
• cain
• Cain
• Cain-coloured
• ca'ing whale