frustrat

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. [ 1913 Webster ]

Shall the adversary thus obtain
His end and frustrate thine ? Milton. [ 1913 Webster ]

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. [ 1913 Webster ]

adv. In vain. [ Obs. ] Vicars. [ 1913 Webster ]

n. an act of hindering someone's plans or efforts.
Syn. -- frustration, thwarting, foiling. [ WordNet 1.5 ]

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 ]

n. [ L. frustratio: cf. OF. frustration. ] The act of frustrating; disappointment; defeat; as, the frustration of one's designs. [ 1913 Webster ]

a. Tending to defeat; fallacious. [ Obs. ] Ainsworth. [ 1913 Webster ]