"Loner" is self-defined.
I am a loner. I always have been, whether I lived alone or with others. I've been married twice, once for 10 years and once for 11 years, and have lived mostly alone for 11 years since my last divorce.
I prefer living alone. I like my privacy. I don't get lonely. I don't need to have people around. I rarely call anyone, including my closest family, and when they call me, it's hard for me to come out of my own head for any longer than 10 minutes or so.
I DO miss being married for all the wrong reasons. What I really need is, not a spouse, but a manager/housekeeper/butler/cook/valet/handyperson/secretary who would, while I was gone, do all the house work, yard work, laundry, barn chores, farm chores, repairs, mundane business phone calls, keep the fire going, etc., and leave a nice warm meal on the stove, but disappear as soon as I got home.
I have some friends that I like, and enjoy occasional social time with. I have a very small family that I adore, and would spend more time with if I worked less. Alone time has to come first, though. Without abundant time alone, I am stressed, depressed, and irritable. Time with people drains me.
I have no problem attending movies, going out to eat, attending parties, etc. alone.
If I had a secure income I didn't have to show up at work for, I'd like to have a square mile of my own property with my house right smack in the center, surrounded by miles of public land, miles and miles and miles away from any paved road or traffic. I could live there without going anywhere for months at a time in perfect peace.
What's you're version of loner?