noun
hot-blooded man; passionate man
Describes a man with a strong sense of justice and intense emotions, often quick to act on his feelings. Can carry a slightly old-fashioned or dramatic tone.
彼は正義感にあふれた熱血漢だ。
He is a passionate man full of a sense of justice.
Compound of 熱血 (hot blood, passion) and 漢 (man). The exact historical derivation is uncertain, but the word likely emerged in modern Japanese to describe an impassioned, righteous man.