背約 [ㄅㄟˋ ㄩㄝ; bei4 yue1]
  to break an agreement
  to go back on one's word
  to fail to keep one's promise
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  背約
  はいやく
  noun (common) (futsuumeishi)
  noun or participle which takes the aux. verb suru
  a broken promise
  breaking one's word
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