Wopple Head

informal. a person who is notably stupid or lacks good judgement. flexible in it's use in that it can be used politely for minor stupidity events, as in children or loved ones, or more strongly as a substitute for cunt, for full fledged retardation.

you're such a wopple head, you should run headfirst into a wall.

look at this wopple head, doesn't even know how to drive his vehicle.

or in the case of a loved one: I'm not a wopple head, you're a wopple head.