Feral or Stray or Outdoor?

Is there a simple way to tell if a cat a feral/stray/outdoor?

There's this one cat that I've seen frequently outside my window in the apartment complex. I've only seen him, and no other cats. No collar.

His fur looks very shiny and clean, his eyes clear and moves very well. He also looks on the average-chubby side (but not sure if pregnant or just chubby)

I've only seen him from the distance from my 2nd floor window. But when I do call out for him (her?), he does stop, look at me.. and occasionally run closer to directly below my window where he'd watch, then crouch to a meatloaf position and slowly blink his eyes,  half closed while watching me as I talk to him.

the times I did see him while I was outside, he'd run away from me and hide. I know his hiding place, it's a nice size crawl space under the apartment building (I can fit in it and move around while hunched over if I wanted to..)

I don't want to feed him, as he looks chubby and doing well for himself, and I don't want him to become dependant on me, especially if he has owners.

What do you think? Does he sound like a stray/feral/outdoor?

some pics:

Doesn't sound feral at all.  A feral would never make eye contact with you and would run at hide at first sight of you.  If you called to a feral they would not respond but instead run and hide.  It sounds like an owned outdoor cat or a stray.  You could always post a sign around your complex or ask around to see if it's someones cat.  The fact that its coat appears shiny, eyes bright and looks well fed leads me to believe it's someones cat. 
 

Yes, it can at times be difficult to tell the difference. Being and looking well fed isn't even always a clue. Though recently abandoned strays usually can look pretty bad. While a feral can actually look pretty healthy. This being because they know how to hunt and survive, while a stray may not yet have learned to do this so well.

He sounds, to me, to be more of either a stray who's being fed, or someones outdoor kitty. Ferals you will rarely see during daylight, they hide from all human activity, unless part of a fed colony. If you do see one and call out, they usually will take off quickly. 

That's what I'm thinkin.. Especially reading your posts.. That he is a stray or outdoor kitty