How to pronounce subtle:
Example: "His whole attitude had undergone a subtle change"
Example: "A subtle mind"
Example: "Glaucoma is an insidious disease"
Hard to grasp; not obvious or easily understood; barely noticeable.
Example: "The difference is subtle, but you can hear it if you listen carefully."
(of a thing) cleverly contrived.
(of a person or animal) cunning, skillful.
Insidious.
Tenuous; rarefied; of low density or thin consistency.
Refined; exquisite.