refinement

The process of removing impurities (as from oil or metals or sugar etc.).

A highly developed state of perfection; having a flawless or impeccable quality.

“I admired the exquisite refinement of his prose”

The result of improving something.

“he described a refinement of this technique”

The quality of excellence in thought and manners and taste.

“a man of intellectual refinement”

A subtle difference in meaning or opinion or attitude.