It usually implies that the stabilizing surface(s) are close to the cg (or wing). I've heard it used in terms of both pitch and yaw.
It means that the surface has to be proportionately larger than if it were not "short coupled". It also means that the interference effects between surfaces will be stronger.
Eurofighter is sometimes called a "short coupled canard delta" which is alluding to the close proximity of canard and mainplane, and the resulting powerful interactions between the two.
F-22 might be called short coupled in pitch too, due to the very close proximity of wing t/e and tailplane l/e.
I don't think there's any particular aircraft characteristic as a result, it's just that the aerodynamics are more interesting.