Mésalliance

Typically used to define a union with a socially inferior partner, like morganatic marriage by a member of royal family, this Gallicism is also used metaphorically, especially in the misalliance variant, to describe a generally unworkable association,[1] for example, the ill-fated alliance of German nobility with Hitler.

The definitions of the "proper marriage" and consequences of ignoring them varied from one culture to another (for example, the nobles in the early modern Europe were expected to avoid marrying commoners, with the considerations for the religion and wealth being of less importance[5]).

For nobles, mésalliance denoted a scandal of a marriage between an aristocrat and a person of lower standing that might involve a loss of rank or inheritance.

The tradition carried over through Mediaeval period (Nibelungen saga) to modern times with the stories of George Dandin, chevalier des Grieux, and the play Misalliance by Bernard Shaw.

[13][2] Painters were attracted to the subject since at least the late 15th century, typically playing on a contrast between a young wife and her old husband, sometimes reversing the ages.