1. [adj]  unproductive of success; "a fruitless search"; "futile years after her artistic peak"; "a sleeveless errand"; "a vain attempt"
2. [adj]  characteristic of false pride; having an exaggerated sense of self-importance; "a conceited fool"; "an attitude of self-conceited arrogance"; "an egotistical disregard of others"; "so swollen by victory that he was unfit for normal duty"; "growing ever more swollen-headed and arbitrary"; "vain about her clothes"

Vain
Vain

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1. \Vain\, a. [Compar. {Vainer}; superl. {Vainest}.] [F. vain,
   L. vanus empty, void, vain. Cf. {Vanish}, {Vanity}, {Vaunt}
   to boast.]
   1. Having no real substance, value, or importance; empty;
      void; worthless; unsatisfying. ``Thy vain excuse.''
      --Shak.
            Every man walketh in a vain show.     --Ps. xxxix.
                                                  6.
            Let no man deceive you with vain words. --Eph. v. 6.
            Vain pomp, and glory of this world, I hate ye!
                                                  --Shak.
            Vain visdom all, and false philosophy. --Milton.
   2. Destitute of forge or efficacy; effecting no purpose;
      fruitless; ineffectual; as, vain toil; a vain attempt.
            Bring no more vain oblations.         --Isa. i. 13.
            Vain is the force of man To crush the pillars which
            the pile sustain.                     --Dryden.
   3. Proud of petty things, or of trifling attainments; having
      a high opinion of one's own accomplishments with slight
      reason; conceited; puffed up; inflated.
            But wilt thou know, O vain man, that faith apart
            from works is barren?                 --James ii. 20
                                                  (Rev. Ver.).
            The minstrels played on every side, Vain of their
            art.                                  --Dryden.
   4. Showy; ostentatious.
            Load some vain church with old theatric state.
                                                  --Pope.
   Syn: Empty; worthless; fruitless; ineffectual; idle; unreal;
        shadowy; showy; ostentatious; light; inconstant;
        deceitful; delusive; unimportant; trifling.
   

2. \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.