thwart

from The American Heritage® Dictionary of the English Language, 5th Edition.

• transitive verb To prevent the occurrence, realization, or attainment of.
• transitive verb To oppose and defeat the efforts, plans, or ambitions of (someone).
• noun A seat across a boat on which a rower may sit.
• adjective Extending, lying, or passing across; transverse.
• adjective Eager to oppose, especially wrongly; perverse.
• adverb & preposition Athwart; across.

from The Century Dictionary.

• noun See the extract.
• noun A seat across a boat on which the oarsman sits.
• Lying or extending across or crosswise; cross; transverse.
• Antithetical.
• Perverse; contrary; cross-grained.
• noun Opposition; defiance.
• To pass over or across; cross.
• To put crosswise, or one across another.
• To put in the way; oppose.
• To cross, as a purpose; contravene; frustrate; baffle.
• Synonyms Foil, Baffle, etc. See frustrate.
• To go crosswise or obliquely.
• To be in opposition; be contrary or perverse; hence, to quarrel; contend.
• From side to side; across; crosswise; transversely; athwart.
• Across; athwart.
• Opposite to; over against.

from the GNU version of the Collaborative International Dictionary of English.

• adverb obsolete Thwartly; obliquely; transversely; athwart.
• transitive verb obsolete To move across or counter to; to cross.
• transitive verb To cross, as a purpose; to oppose; to run counter to; to contravene; hence, to frustrate or defeat.
• adjective Situated or placed across something else; transverse; oblique.
• adjective obsolete Fig.: Perverse; crossgrained.
• noun (Naut.) A seat in an open boat reaching from one side to the other, or athwart the boat.
• preposition Across; athwart.
• preposition See Athwart ships, under Athwart.
• intransitive verb rare To move or go in an oblique or crosswise manner.
• intransitive verb rare Hence, to be in opposition; to clash.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive to prevent; to halt; to cause to fail; to foil; to frustrate.
• noun nautical A brace, perpendicular to the keel, that helps maintain the beam (breadth) of a marine vessel against external water pressure and that may serve to support the rail.
• noun nautical A seat across a boat on which a rower may sit.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb hinder or prevent (the efforts, plans, or desires) of
• noun a crosspiece spreading the gunnels of a boat; used as a seat in a rowboat