Similar to fucktard, this word is a portmanteau of cunt and retard. While fucktard is associated with activly acting like a fucking retard, a cuntard is more passive and just sits there acting like a retarded cunt.
(noun) A female, who like her male counterpart known as the munt, acts irresponsible and reckless in her behavior where social graces, common etiquette, and/or her general disregard for fellow humans is concerned.
Her friend treated her like a real cuntard when she learned she bought the same dress for the dance.