Synonyms: let down, disappoint
Definition: fail to meet the hopes or expectations of
Usage: Her boyfriend let her down when he did not propose marriage
Similar words: spoil, scotch, queer, thwart, bilk, baffle, foil, frustrate, cross
Definition: hinder or prevent (the efforts, plans, or desires) of
Usage: What ultimately frustrated every challenger was Ruth's amazing September surge; foil your opponent