Vain, n. Vanity; emptiness; -- now used only in the phrase in vain.
  For vain. See In vain. [Obs.] --Shak.
  In vain, to no purpose; without effect; ineffectually. “ In vain doth valor bleed.” --Milton. “ In vain they do worship me.” --Matt. xv. 9.
  To take the name of God in vain, to use the name of God with levity or profaneness.
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