Middle English: shortening of Old French e(s)vaniss-, lengthened stem of e(s)vanir, from Latin evanescere 'die away'.

• vanity from Middle English:

  In early use vanity meant ‘futility, worthlessness’, with the idea of being conceited recorded a century later. This is the quality condemned in ‘Vanity of vanities; all is vanity’ from the biblical book of Ecclesiastes. The source of the word is Latin vanus ‘empty, without substance’, also the source of vain (Middle English) and vanish (Middle English). In The Pilgrim's Progress by John Bunyan, published in 1678, Vanity Fair is held in the town of Vanity, through which pilgrims pass on their way to the Eternal City. All kinds of ‘vanity’, things of no real value, were on sale at the fair. The 19th century took the name Vanity Fair to represent the world as a place of frivolity and idle amusement, most notably in Thackeray's novel Vanity Fair (1847–48). Vanity Fair has been the title of four magazines since the 1850s, in particular the current US one founded in 1914. From its earliest appearance in around 1300 vain has meant ‘lacking real worth, worthless’. To take someone's name in vain, ‘to use someone's name in a way that shows disrespect’, echoes the third of the biblical Ten Commandments: ‘Thou shalt not take the name of the Lord thy God in vain.’ Since the late 17th century vain has also described someone who has a high opinion of their own appearance.