vainveɪn(adj.)-er, -est.

1. excessively proud of or concerned about one's own appearance, qualities, achievements, etc.

2. proceeding from or showing personal vanity.

3. futile:

   vain efforts.

4. without real significance.

5. Archaic. senseless or foolish.

Idioms for vain:

1. in vain, without effect or avail; to no purpose. in an improper or irreverent manner:

   to take God's name in vain.

   Category: Idiom

Origin of vain:

1250–1300; < OF < L vānus empty, vain

vain′ness(n.)