mesalliance

/ˌmeɪzəˈlaɪəns/
noun
  1. A marriage with a person of a lower social class or status.
    • In many old novels, a mesalliance is a source of family conflict.
    • The duke's mesalliance with a commoner shocked the royal court.
    • Her parents disapproved of the mesalliance, fearing it would harm their social standing.
Synonyms