vanish: [14] To vanish is etymologically to ‘become empty’. The word comes via Old French esvanir ‘disappear’ from Vulgar Latin *exvānīre, a variant of Latin ēvānēscere ‘disappear’ (source also of English evanescent [18]). This was a compound verb formed from the prefix ex- ‘out’ and vānus ‘empty’ (source of English vain, vanity, vaunt, etc). => evanescent, vain, vanity, vaunt
vanish (v.)
"disappear quickly," c. 1300, from shortened form of esvaniss-, stem of Old French esvanir "disappear; cause to disappear," from Vulgar Latin *exvanire, from Latin evanescere "disappear, pass away, die out," from ex- "out" (see ex-) + vanescere "vanish," inchoative verb from vanus "empty" (see vain). Related: Vanished; vanishing; vanishingly. Vanishing point in perspective drawing is recorded from 1797.