vain的名词是：vainness。vain近义词useless。vain的读音是英[ve_n]；美[ve_n]。
一、详尽释义
adj.(形容词)自负的，自视过高的，自高自大的徒然的，徒劳的，无结果的，枉然的无益的爱虚荣的炫耀的空虚的无意义的，无价值的无效的，没效果的愚蠢的n.(名词)未用空间二、双解释义
adj.(形容词)自负的; 爱慕虚荣的 thinking too highly of one's appearance, abilities, etc.; conceited徒劳的,无用的,无效的 useless or futile三、词典解释
1.徒劳的;无效的;不成功的
Avain attempt or action is one that fails to achieve what was intended.
vain什么意思
e.g. The drafting committee worked through the night in avain attempt to finish on schedule...
起草委员会为按计划完成草案已通宵加班，但结果仍是徒劳。
e.g. I was singing in avain effort to cheer him up.
我唱歌试图让他高兴起来，结果是白费力气。
vainly
He hunted vainly through his pockets for a piece of paper.
他翻遍口袋想找一张纸，结果没找到。2.徒然的;无望的
If you describe a hope that something will happen as avain hope, you mean that there is no chance of it happening.
e.g. He married his fourth wife, Susan, in thevain hope that she would improve his health.
他娶了第四个老婆苏珊，徒然希望她能使他健康状况好转。
vainly
He then set out for Virginia for what he vainly hoped would be a peaceful retirement.
于是他动身前往弗吉尼亚，幻想能够平静引退。3.自负的;虚荣的;自命不凡的
If you describe someone asvain, you are critical of their extreme pride in their own beauty, intelligence, or other good qualities.
e.g. I think he is shallow,vain and untrustworthy.
我认为他浅薄虚荣，不可信任。
4.徒劳;白费力气
If you do somethingin vain, you do not succeed in achieving what you intend.
e.g. He stopped at the door, waiting invain for her to acknowledge his presence...
他在门口停住，徒然地等待她和自己打招呼。
e.g. It became obvious that all her complaints were invain.
很明显她所有的抱怨都是白费口舌。
5.无用的;无意义的;无价值的
If you say that something such as someone's death, suffering, or effort wasin vain, you mean that it was useless because it did not achieve anything.
e.g. He wants the world to know his son did not die invain.
他想让全世界都知道，他的儿子不是白白死去的。
四、例句
She is vain and foolish, and yet people like her.
她自负而愚蠢，然而人们喜欢她。
She is vain of her voice.
她自以为她的声音了不起。
They endeavoured to make her happy but in vain.
他们尽量使她快乐，却徒劳无功。
All his father's exhortations were in vain.
他父亲的一切劝告都无效。
We tried in vain to make him change his mind.
我们想使他改变主意，结果是白费心机。
The world had made him extravagant and vain.
世俗使他变得放荡不羁，虚荣自负。
She is so vain that she can't pass a mirror without looking into it.
她好爱虚荣,每经过一面镜子都要照一下。
五、常见句型
用作形容词(adj.)用作定语～+ n.She is one of those vain people who never take others' advice.
她属于那种自负得从不听别人劝告的人。I don't like a vain woman.
我讨厌爱慕虚荣的女人。He made a vain attempt to reach the drowning child.
他试图接近那个快淹死的小孩,但没有成功。用作表语S+be+～All my efforts were vain.
我的一切努力都白费了。S+be+～+ prep .-phraseHe's very vain of his abilities.
他对于自己的能力很自负。It is/was+～+to- vIt is vain to resist.
抵抗是没用的。用作宾语补足语S+V+O+～Too much praise can make a man vain.
过度的赞扬会使人自负。六、经典引文
All literature, art, and science are vain..if they do not enable you to be glad.
出自：J. RuskinIt is..vain to try to be other than we are.
出自：D. M. FrameThe vain attempts of feminist critics to prove there is a..'women's language'.
出自：New York Review of Books七、词源解说
☆ 直接源自古法语的vain，意为没有价值的；最初源自拉丁语的vanus，意为空着的。vain的相关近义词
useless、void
vain的相关反义词
beneficial、effective、useful
vain的相关临近词
val、vail、Vaino、Vaini、Vaina、Vaine、Vainio、Vainar、vainly、Vaindl、Vainkop、Vainsot