What does the word vain mean?

Usage examples for vain

  1. Each tried very hard to find something to say, but in vain. – The Star-Gazers by George Manville Fenn
  2. Not in vain, dearest! – Barren Honour: A Novel by George A. Lawrence
  3. I wonder if you'd think me vain if I asked you something that I want to know? – Work: A Story of Experience by Louisa May Alcott