a marriage with a person of inferior social status, as George Dandin to his wife
it literally means "mis-alliance"
► uses
Uses:
Whether she was black-tressed Melpomene, with bowl and dagger, or Thalia, with the fair hair and the laughing face, was only to be guessed at. It was popularly conceded, however, that Van Twiller was on the point of forming a dreadful mésalliance.
Thomas Bailey Aldrich. Mademmoiselle Olympe Zabriski
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the prince would no longer be making a mesalliance by marrying you,” and Bilibin smoothed out his forehead.