Vain describes someone who cares too much about their appearance or thinks too highly of themselves. A vain person might spend hours admiring themselves in mirrors, constantly fishing for compliments about how they look, or talking endlessly about their own achievements.

The word carries a negative judgment. While it's fine to take pride in your work or care about looking neat, a vain person crosses into territory where self-admiration becomes their main focus. Someone vain might ignore important conversations because they're too busy checking their reflection, or they might steer every discussion back to themselves.

The word also appears in the phrase in vain, which means without success or for no purpose. If you search in vain for your lost backpack, you looked everywhere but never found it. When someone says “I tried in vain to explain the math problem,” they mean their efforts didn't work.

Vanity is the noun form. The villain in Snow White shows vanity when she obsesses over being “the fairest of them all.” Vanity can drive people to make foolish choices, since they care more about appearance than substance. A student showing vanity might worry more about looking smart during a presentation than actually understanding the material they're presenting.