Ring IQ, doesn't matter what your physical attributes are, if you're too dumb to maximise them or worse, fight in a manner that exposes your weaknesses for opponents to exploit then those gifts become irrelevant.
Gift is something that cannot be given. You can teach a boxer. I would say athleticism, as is for near any other athlete. The age old comparison: put a black belt child in with an adult. Put an 85 year old grandmaster in with a 27 year old in his athletic prime.
Power. Because everything can be added on after that. Plus they all hit hard at the world class level usually I meant. Even if you had a crappy trainer, could block basic punches and could throw a good one two and had a penchant/ leaning/ liking towards fighting you could always add more ring iq. Jmo
All of that thinking would go out the window against some crazed psychopath who only cares about spamming power shots to the ribs to tenderize them.
Sorry the most important Gift in Boxing? Then It's A chin. Which I don't have. Hence the name....... NoChin.
If you're a prize fighter and you can't take a pop on the whiskers get your pathetic defective genes ass the hell out of my sport ASAP you worthless piece of subhuman trash. Apologies if I come across as too harsh but this is a subject I feel very strongly about. There is simply no place in the sport for disgusting glass-jawed or below average punch resistance vermin. They are not only a blight and an embarrassment on the sport and the iron-jawed warriors who came before them, they are a blight and an embarrassment to our species.