I'm with Pacer on the definition here.
And I agree with being "one with your rifle". You have no idea how many people I see come into the store and ask to see a rifle. Watch them throw it up to their shoulder and they say things like "Yeah, that's nice" or "Wow, handles sweet." But their body language tells me otherwise; they LOOK like they're trying to bend around this chunk of wood (or plastic) and steel, and it definitely is not "familiar" to them in any way. No matter which rifle they pick up.
For me, my "go-to" rifle will always be an AR-15. I have spent thousands of rounds and who knows how many hours getting familiar with them. I'm not military or police; I'm a Highpower shooter. And just because I'm accustomed to drilling little groups in targets slung up doesn't mean I can't hit something when I'm just given a rifle and let-loose!
If anything, it comes down to practice and proficiency. No matter who trained you and what you do, if you can pick up a rifle and start hitting 300-yard targets (and further) with a little familiarization, you're a pretty good rifleman in my book.
And I also think there's a difference between combat ability and just being a plain good shooter. I've met plenty of former military, police and former police officers who are going to be much, much better at staying alive in a fight than I ever will. But I am certainly not going to back down on survival ability (in the woods) and ability to shoot at (and hit!) things.
Edited: Actually, one of the old cops I know is a little paranoid of spending a night in the woods. I always remind him, "Around here, just walk in a straight line for 5-6 hours; you'll find something."