refine

Etymology

re- + fine

verb

1. (transitive) To purify; reduce to a fine, unmixed, or pure state; to free from impurities.
   to refine gold
   to refine iron
   to refine wine
   to refine sugar
   The dawn of the oil age was fairly recent. Although the stuff was used to waterproof boats in the Middle East 6,000 years ago, extracting it in earnest began only in 1859 after an oil strike in Pennsylvania.[…]It was used to make kerosene, the main fuel for artificial lighting after overfishing led to a shortage of whale blubber. Other liquids produced in the refining process, too unstable or smoky for lamplight, were burned or dumped. 2013-08-03, “Yesterday’s fuel”, in The Economist, volume 408, number 8847
2. (intransitive) To become pure; to be cleared of impure matter.
3. (transitive) To purify of coarseness, vulgarity, inelegance, etc.; to polish.
   to refine someone's manners
   to refine a language
   a refined style
   to refine one's tastes
4. (transitive, intransitive) To improve in accuracy, delicacy, or excellence.
   My dear Harriet, you must not refine too much upon this charade.—You will betray your feelings improperly, if you are too conscious and too quick, and appear to affix more meaning, or even quite all the meaning which may be affixed to it. 1815, Jane Austen, Emma, volume I, chapter 9
5. (transitive) To make nice or subtle.
   to refine thought
   to refine someone's language