A heavy disruptor was a type of weapon, a much more powerful version of a standard disruptor.
As ship-mounted weapons, heavy disruptors were being introduced in the late-23rd century Klingon Empire in the years before the peace treaty with the Federation in the 2290s decade. The Tholians were also known to utilize these weapons on their starships. The weapons' power yield has been described as a little over half the damage that a standard photon torpedo was capable of accomplishing. (TOS video game: Klingon Academy)