The weight that a fighter carries while being lean and trim and without any excess muscle mass built up by weight training. If a fighter has excess bodyfat or big, ripped muscles, he's not at his natural weight.
There's no such thing. The reason boxers move up in weight is not because they are looking for a new chalange. The reason is that their bodies can't keep making weight as they get older. As you grow older your metabalism slows down. The result is that even with the most decataed fitness/nutrition routine it becomes pretty much imposible to make a lower weight with out being drained.
Weight that has not been fiddled with. Artificial joints, pins, plates and such are examples of what can be described as 'unnatural weight.' Gold/silver teeth and body piercings may also contribute.
I am so sick and tired of all of these threads about weight...this is so overrated. The more pressing question is what is a fighters natural height, this is where real greatness lies! Has anyone done a study to determine how a fighters height varies through his career?