When you're lying awake with a dismal headache, and repose is taboo'd by anxiety, I conceive you may use any language you choose to indulge in, without impropriety.

-Gilbert, Sir W(illiam) S(chwenck)
  Lord Chancellor's nightmare song, Iolanthe, act 2.

Impropriety is the soul of wit.

-Maugham,W(illiam) Somerset
  The Moon and Sixpence.

There was no impropriety whatsoever in my acquaintanceship with Miss Keeler† I shall not hesitate to issue writs for libel and slander if scandalous allegations are made or repeated outside the House.

-Profumo,John Dennis
  House of Commons, Mar.