By Breaking Celebrity News Staff

Carole Radziwill and Countess LuAnn De Lesseps clash over a racially insensitive faux pas in a preview clip from Monday's upcoming Real Housewives of New York City.

LuAnn's use of the phrase "Indian" -- in lieu of Native American -- irritates Carole, who informs her, "Anyone over the third grade knows not to say 'Indian.'"

The beautiful Countess -- who has Native American blood on her father's side -- responds by chanting while patting her mouth, mocking Carole's cultural sensitivities.

Carole incredulously says, "Native American … I don't know … everyone over the third grade …"

The Countess tries to blow it off, saying her boyfriend "always calls me his Wild Indian," which doesn't offend her.

Carole says in an off-camera interview that the LuAnn's words rubbed her the wrong way, as Native Americans have a "history of being neglected, discriminated against and abused.

"And that is something you don't joke about," she adds.