BoxRec

I've often heard these words used interchangeably for fighters. What exactly is the difference?

ken norton was athletic, muhammad
ali was fast.

mike tyson and joe frazier were very fast, but unathletic.
athletic generally refers to running jumping all-around athlete potential,
like if the guy looks like carl lewis. being a natural athlete helps as much
in boxing as it does in any other sport. in boxing, fast refers to reflexes and
ability to get a punch off quickly, which comes from technique and muscle
memory.

In a boxing context many use 'athletic' vaguely with little indication of what they mean. I think a fair proportion of these people define fighters as athletic or not in significant part based on physical appearance, meaning that some fighters with very similar abilities to those who are considered athletic don't get the label applied to them.

More specifically, I believe that blacks generally have a reputation for being relatively athletic (germane article here http://www.u.arizona.edu/~jeffs/golf1.pdf), and from my experience virtually every boxer who gets called athletic is black.

there is no clear definition....in the internet you can read something like this

adjective
1.
physically active and strong; good at athletics or sports:

to me, it depends in which sport you are.

in 100 m sprint you are very athletic when you run fluidly and very fast, but sure, usain bolt would be unathletic in a boxing ring, cause in boxing athletic means to me, that you're body, you're physic is so athletic that you can move fluiidly lateral, you're upper body movemant, you're footwork, you're handspeed.