tough guy; fearless fighter; wild one
Refers to a strong, brave, or reckless person, often with a rough or wild image. Can be used admiringly or critically.
彼は戦場で猛者として知られていた。
He was known as a fearless fighter on the battlefield.
あの新入社員はなかなかの猛者だ。
That new employee is quite a tough guy.
He is known as a fearsome veteran in the judo world.
Tough fighters gather at this dojo from all over the country.
This team is full of fearsome veterans, so no one can afford to let their guard down.
豪傑 is a more literary, larger-than-life hero, whereas 猛者 is a colloquial term for an everyday tough guy.
弱者 refers to a weak or vulnerable person, the opposite of the fearless, tough 猛者.
Standard kanji spelling.
The kanji 猛 means 'fierce' or 'wild', and 者 means 'person'. The reading もさ is a standard on'yomi combination. The obsolete reading もうざ reflects an older pronunciation.