Well, it implies that, first, he was hired (it would require some level of skill), and, second, that he survived. Ancient/medieval melee battles were not a mean feat, and swinging a sword or shooting a bow for extended periods of time, while trying not to be slaughtered, was extremely tiring. Those who were incapable, or did not know what they were doing, did not survive.
In modern literature I think of Bronn from ASoIaF, who was a tough and vicious bastard, not afraid to fight dirty. A company of men like this, who make it their craft to fight wars for money, and do it for years, is not easily killed, and they won't be easily bullied or scared into submission. Bad for business.