If you refer to someone's vanity, you are critical of them because they take great pride in their appearance or abilities.
例句
Men who use steroids are motivated by sheer vanity...使用類固醇的男人純粹是受虛榮心的驅使。With my usual vanity, I thought he might be falling in love with me.由于我一貫的虛榮心作祟，我以為他可能愛上了我。
英漢詞典釋義
n.
自負；自大；虛榮；虛榮心
The woman is always feeling after vanity.這女人一貫追求虛榮。
英英詞典釋義
Noun
1. feelings of excessive pride
2. the quality of being valueless or futile;
"he rejected the vanities of the world"
3. the trait of being vain and conceited
4. low table with mirror or mirrors where one sits while dressing or applying makeup