oil and water don't mix

== English == === Proverb === oil and water don't mix (dated, derogatory, offensive, proscribed) Black people and white people should not form relationships; an admonition against interracial relationships. (more generally) Some people, things, or characteristics do not go together. Used other than figuratively or idiomatically: see oil,‎ water,‎ don't,‎ mix.