Meaing a very learned person.
The word virtuoso (from latin virtuosus) is an Italian word meaning in English "an individual who possesses outstanding excellence" in any specified field. Thus virtuoso violinist simply means...
a virtuoso on any instrument is pretty much an absolute master of their instrument. They are the best musicians in the world.
Bach Mozart
Virtuoso violinist Isaac Stern is one of the most renowned and celebrated musicians of our time