you could say mclellan was tough for carrying on in the benn fight when god knows what was going through his head. yes he quit in the end but 5 minutes later he was heading into a coma.michael watson also was extremely tough to come out for the 12th round of the eubank fight although he should not have been allowed, and also he only got stopped off mike mccallum through sheer exhaustion, he was beckoning mcallum in in the 12th. his fight back to relative health after nobody gave him a chance shows toughness too. not saying these 2 are the toughest by the way, just examples.
Wayne McCullough. was able to take an amazing amount of punishment and still keep coming forward! Pity he hadnt a bigger punch!
Chuvalo,Benn,McCullough,La Motta Honourable mention-McClellan(agree with smiffy he must have been going through hell), Watson,Hagler,Gatti, too many to mention.
Is toughest defined by never being dropped or hurt, or being hurt and dropped and coming back with even more fire?
OK, then let us say the toughest fighter inside the ring...he had the flu and canceled the fight before it began. He didn't quit during the fight.
Carmen Basilio. Lamotta quit, Morales quit, Chacon quit. Plenty of guys quite, but Basilio never did, and his chin is every bit as good as LaMotta or Chuvalo.