thwart

Noun

• a crosspiece spreading the gunnels of a boat; used as a seat in a rowboat

Verb

• hinder or prevent (the efforts, plans, or desires) of
  • What ultimately frustrated every challenger was Ruth's amazing September surge
    
  • foil your opponent
    

Related words

• Synonyms: 
  cross thwart , queer , spoil , scotch , foil , cross , frustrate , baffle , bilk