In aviation, maneuvering speed is the highest speed at which full deflection of the controls about any one axis are guaranteed not to overstress the airframe.
I often worry about this particular definition. If you refer to FAA Advisory Circular 23-19, paragraph 48, it clearly warns:
"VA should not be interpreted as a speed that would permit the pilot unrestricted flight-control movement without exceeding aircraft structural limts"
VA is used to design the empennage and ailerons.
A speed known as "operating speed" (VO), defined in FAR 23.1507 is probably closer to the average pilot's definition of maneuvering speed.
But to sow some confusion, the FAA "Pilot's Handbook of Aeronautical Knowledge" defines VA as the "maximum airspeed to which the limit load can be imposed (either by gusts or full deflection of the control surfaces) without causing structural damage". Which suggests that the people who design the aircraft and the people who fly the aircraft may not be using the same definition!