A humble man falls in love with himself; a vain man falls in love with his reflection.

一个谦虚的人爱上的是他自己；而一个虚荣的人爱上的却是自己的倒影。

youdao

She closed her eyes tightly in a vain attempt to hold back the tears.

她紧闭双眼，却无法忍住眼泪。

《牛津词典》

It was a vain attempt to shift the responsibility for the murder to somebody else.

把这项谋杀的罪责转嫁于他人是徒劳之举。

《柯林斯英汉双解大词典》

It is rather for us to be here dedicated to the great task remaining before us that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion that we here highly resolve that these dead shall not have died in vain that this nation,under God, shall have a new birth of freedom and that government of the people, by the people,for the people, shall not perish from the earth."

VOA: special.2009.11.12

Specifically you'll see that the rationale for observing the Sabbath is different. God's name in Deuteronomy 5 is not to be used in a vain oath as opposed to a false oath. There are differences in the meaning.

你会发现两者对守安息日习俗的论述是特别不同的,《申命记》第五章的描述是，不可以妄称上帝的名,而不是不可以以上帝的名义作假誓，它们表达的意思。

耶鲁公开课 - 旧约导论课程节选

And it's not just the accent of "Ain," "Quatre-vain" Or "Enfain" Instead of enfin-- it's a whole language.

而且不光是那种"俺"的口音,"把十"或者"嗨子"而不是孩子,完全是另一种语言

耶鲁公开课 - 1871年后的法国课程节选

Since April the pace of appreciation has been much reduced, in a vain effort to discourage speculators.

ECONOMIST: Capital inflows to China

It is likely to be a vain exercise: unnecessary if the downturn is mild, but insufficient to deal with a truly dire mess.

ECONOMIST: America's economy

It tells of a strange child's forlorn travels through the universe after quitting his native planet, B-612, to escape a vain, capricious rose.

ECONOMIST: Hunting for Saint-Exup��ry