What does the word expletive mean?

Usage examples for expletive

  1. Green bit back an expletive. – The Grell Mystery by Frank Froest
  2. That might explain-" An expletive smacking more of Montmartre than of the Boulevard Capucines, fell from the nobleman's lips. – A Man and His Money by Frederic Stewart Isham
  3. The Bish made use of a very unorthodox expletive. – Fore! by Charles Emmett Van Loan