A fork of Rural Dictionary
Named after the rabbit from Disney's Bambi, whose father told him "If you don't have anything nice to say, don't say anything at all." It is way of teaching of keeping derogatory comments to oneself in respect to those who aren't as able as you are to avoid conflict.
Male 1: Man, that a-hole is such a-
Male 2: Hey, remember Thumper's Law man.
Male 1: Fine, don't want any problems anyway.