"to bring or reduce to a pure state or a condition of purity as full as possible," 1580s of metals; c. 1590 of manners ("purify from what is coarse, low, vulgar, inelegant, etc.;" from re-, here perhaps an intensive prefix, + obsolete fine (v.) "make fine," from fine (adj.) "delicate." Compare French raffiner, Italian raffinare, Spanish refinar. General and figurative sense is recorded from 1590s; of sugar from 1610s. Intransitive sense of "become pure" is from c. 1600. Related: Refined; refining.