Vainest

adjective

1. Overly proud of oneself, especially concerning appearance; having a high opinion of one's own accomplishments with slight reason.
2. Having no real substance, value, or importance; empty; void; worthless; unsatisfying.
3. Effecting no purpose; pointless, futile.

   "vain toil;  a vain attempt"

4. Showy; ostentatious.