(verb): to knock, pound, or rap on a wall, floor, or ceiling, whether manually or with an object, in response to undesired sound coming from the other side.
(noun): an act or instance of "knocking back" in response to such a noise.
(verb) Geez, it's 1 AM and their stereo is still blaring. I've gotta knockback.
(noun) They gave us the knockback until we quieted down.