Iv'e known many people who are considered excellent riflemen. I'd like to think that I'm one, but I haven't competed in any 3 or 4 position rifle matches.
Anyway, my definition would have to include someone who enjoys many different types of rifle shooting, from plinking to benchrest. What really separates the rifle shooters from the Riflemen (and Riflewomen) in my mind, is the ability to shoot very well OFFHAND at relatively long distances, usually without special aids like shooting jackets and slings.
My rifleman usually uses an accurate rifle, often a bolt action, often with handloaded ammunition, and can keep most centerfire shots within a 4" circle, standing without support (offhand), at 100 yards.
Your opinion may vary. What would this board be without our different opinions. A wise person once told me, "It's okay to disagree, just not to be disagreeable about it."