refinement has 13 distinct synonyms spread across 5 of its 5 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a highly developed state of perfection; having a flawless or impeccable quality
“they performed with great polish”
the result of improving something
“he described a refinement of this technique”
the process of removing impurities (as from oil or metals or sugar etc.)
the quality of excellence in thought and manners and taste
“a man of intellectual refinement”
Synonyms, antonyms and the broader and narrower relations for refinement come from Princeton University’s WordNet. Full sources and licences.