refinement vs subtlety

refinement and subtlety both are nouns.

Word	Noun	Adjective	Verb	Adverb
refinement	Yes	No	No	No
subtlety	Yes	No	No	No

As nouns, refinement and subtlety are synonyms defined as:

refinement and subtlety: a subtle difference in meaning or opinion or attitude

Other synonyms of refinement include nicety, nuance, shade.

refinement (noun)	subtlety (noun)
the quality of excellence in thought and manners and taste	the quality of being difficult to detect or analyze
a subtle difference in meaning or opinion or attitude	a subtle difference in meaning or opinion or attitude
the result of improving something
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