I find the old boxer-slugger-swarmer categorization a bit outdated but I also think that boxing is one of the sports where some fighters are hard to put into categories. I still do it cause somehow I like that part, like to think about a system behind it.
I generally call brawlers fighters who are less focused on technique, offensive and trust very much in their incentives such as being tough, having the better chin, packing the better punch. They can be awkward because of this too. Brawler often used as a pejorative word but I view it as neutral, a brawler can be great too, arguably the likes of Marciano, Foreman, Holyfield or Lamotta were brawlers too and they were all great. From recent years you can think about fighters like Maidana, Rios, Porter, Matthysse, Provodnikov or Mayorga as brawlers.
King Sor can be a brawler too when he wants to be.
Swarmer is imo a subcategory of brawler or can be called another category too if u want to. I call swarmers the hyper-aggressive, no holds barred fighters. That doesn't necessarily mean they don't defend though...
Frazier, early Tyson, Aaron Pryor, Henry Armstrong etc... from today Shawn Porter is like that (not the same league as the ones mentioned before him just the style itself...)
not all offensive fighters are brawlers though
The GGG like more methodical pressure fighters are not brawlers imo. They don't take as many risks defense wise and rather than beating the opponent through the ring they want to corner him or press him to the ropes with aggressive footwork and jabs to tee off on him there. They usually don't really fight on the inside or get physical either like brawlers often do, they are clinical and they keep it at mid distance.
And then there are the very offensive end of boxer-punchers, fighters like Kovalev who are beating you up constantly but almost always from the outside, never at close range, they keep a preferred range all the time and they can box without a problem too. If they are too close to the opponent rather than roughing him up and throwing uppercuts and hooks, they take a step back and throw straights again.
