• adj. 徒劳的；自负的；无结果的；无用的

来自拉丁语vanus,空的，虚无的，来自PIE*wa-no,分开的，遗弃的，词源同vacate,want,wane.

vain

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.

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.

她被认为是个被人惯坏了的、既虚荣又淫乱的女人。

来自柯林斯例句

5. He was self-important, vain and ignorant.

他傲慢自负，虚荣无知。

来自柯林斯例句