frustrate

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To prevent from accomplishing a purpose or fulfilling a desire; thwart: A persistent wind frustrated my attempt to rake the lawn.
2. v. To cause feelings of discouragement or bafflement in.
3. v. To make ineffectual or invalid; nullify.

Century Dictionary and Cyclopedia

1. To make of no avail; bring to nothing; prevent from taking effect or attaining fulfilment; defeat; disappoint; balk: as, to frustrate a plan, design, or attempt; to frustrate the will or purpose.
2. To make null; nullify; render of no effect: as, to frustrate a conveyance or deed.
3. To defeat the desire or purpose of; cause to be balked or disappointed; thwart.
4. Synonyms Frustrate, Foil, Thwart, Baffle, Balk, are strong words, expressing the complete defeat of any plan or endeavor. Frustrate, to make vain, cause to be in vain, bring to naught. Foil, to stop, render useless. (Foil is not thought to be derived from the use of a foil in fencing, but is associated with it in many minds, and in meaning corresponds with the turning aside of a sword by the address of a fencer.) Thwart, literally, to stop by a bar or barrier, cross effectively, defeat. Baffe, to check at all points or completely and promptly, so that one is at a loss what to do. Balk, to stop in a course, make unable to proceed in a given direction. Perhaps baffle expresses most of confusion of mind or bewilderment, and balk most of annoyance or vexation.
5. Vain; ineffectual; useless; unprofitable; null; void; of no effect.
6. Defeated.
7. n. A weak contraction of the ventricle of the heart, the impulse of which is imperceptible at the wrist, giving the impression of intermittent pulsations.

Wiktionary

1. v. To disappoint or defeat; to vex by depriving of something expected or desired.
2. v. To hinder or thwart.
3. v. To cause stress or panic
4. adj. vain; ineffectual; useless; nugatory

GNU Webster's 1913

1. adj. Vain; ineffectual; useless; unprofitable; null; voil; nugatory; of no effect.
2. v. To bring to nothing; to prevent from attaining a purpose; to disappoint; to defeat; to baffle
3. v. To make null; to nullifly; to render invalid or of no effect.

WordNet 3.0

1. v. hinder or prevent (the efforts, plans, or desires) of
2. v. treat cruelly