The term Cardies was offensive slang for Cardassians.
Makbar once cited with offense a quote from Miles O'Brien: "The bloody Cardies can't be trusted!" (DS9: "Tribunal", "Empok Nor") As a matter of fact, O'Brien used this term on numerous occasions. (DS9: "Emissary", "Captive Pursuit", "The Homecoming", "The Siege")
Cadet Tim Watters used the term Cardies. (DS9: "Valiant")