"Toprudder" is a term used by aerobatics pilots. It is the application of rudder during a rolling maneuver to help maintain altitude. Most aerobatic planes can fly "knife edge", during which the wings are vertical instead of horizontal. "Toprudder" is used to yaw the airplane so that the side area of the fuselage provides enough lift to maintain altitude.
In a greater sense, it means maintaining course by adapting to an unusual or imperfect situation.