Frustrate \Frus"trate\, v. t. [imp. & p. p. {Frustrated}; p. pr.
   & vb. n. {Frustrating}.]
   1. To bring to nothing; to prevent from attaining a purpose;
      to disappoint; to defeat; to baffle; as, to frustrate a
      plan, design, or attempt; to frustrate the will or
      purpose.
      
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            Shall the adversary thus obtain
            His end and frustrate thine ?         --Milton.
      
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   2. To make null; to nullifly; to render invalid or of no
      effect; as, to frustrate a conveyance or deed.

   Syn: To balk; thwart; foil; baffle; defeat.
        
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frustrating \frustrating\ n.
   an act of hindering someone's plans or efforts.

   Syn: frustration, thwarting, foiling.
        [WordNet 1.5]

frustrating \frustrating\ adj.
   1. preventing realization or attainment of a desire; causing
      frustration.

   Syn: frustrative, thwarting.
        [WordNet 1.5]

   2. discouraging. Opposite of {encouraging}.

   Syn: disappointing.
        [WordNet 1.5]