Over Unity

A gain of energy over 100% without input or transfer of energy from other sources to achieve that gain. Most right thinking scientists are in solid agreement that this is absolutely impossible within the current physics framework, the only exception is heat-transfer pumps that output more energy than you put in because they pull the excess energy in from a different source than the one driving the pump.

Anybody that makes claims to the contrary is probably either delusional or out to get your $.