vain: [13] Latin vānus meant ‘empty’ (it was related to vacuus ‘empty’, source of English vacuum). It passed into English via Old French vain in the sense ‘worthless’, and the main modern meaning ‘conceited’ did not develop until the 17th century. Also from vānus come English evanescent, vanish, vanity [13], and vaunt [14], and wane, want, etc go back to the same ultimate Indo-European base. => evanescent, vanish, vanity, vaunt, wane, want
vain (adj.)
c. 1300, "devoid of real value, idle, unprofitable," from Old French vain, vein "worthless, void, invalid, feeble; conceited" (12c.), from Latin vanus "empty, void," figuratively "idle, fruitless," from PIE *wa-no-, from root *eue- "to leave, abandon, give out" (cognates: Old English wanian "to lessen," wan "deficient;" Old Norse vanta "to lack;" Latin vacare "to be empty," vastus "empty, waste;" Avestan va- "lack," Persian vang "empty, poor;" Sanskrit una- "deficient," Armenian unain "empty").
Meaning "conceited, elated with a high opinion of oneself" first recorded 1690s in English; earlier "silly, idle, foolish" (late 14c.). Phrase in vain "to no effect" (c. 1300, after Latin in vanum) preserves the original sense. Related: Vainly; vainness. Compare also vainglory.
实用例句
1. He is still vain enough to dye his hair red.
他还是很虚荣，把头发染成了红褐色。
来自柯林斯例句
2. It became obvious that all her complaints were in vain.
很明显她所有的抱怨都是白费口舌。
来自柯林斯例句
3. I am not a vain creature.
我不是个爱慕虚荣的人。
来自柯林斯例句
4. She is perceived as vain, spoilt and promiscuous.