WordWeb Online

1. Characteristic of false pride; having an exaggerated sense of self-importance
   "vain about her clothes";
   - conceited, egotistic, egotistical, self-conceited, swollen, swollen-headed, proud, puffed-up [informal], swellheaded [N. Amer, informal]
    
2. Unproductive of success
   "a vain attempt";
   - bootless, fruitless, futile, sleeveless

Sounds like: vails, vain, van

Derived forms: vainest, vainer

See also: proud, unproductive

Encyclopedia: Vain