noun
professional boxer; prizefighter
Refers to a boxer who competes professionally, as opposed to an amateur. The term is a direct loan from English.
彼はプロボクサーになるために毎日練習している。
He practices every day to become a professional boxer.
あのプロボクサーは世界チャンピオンを目指している。
That professional boxer is aiming for the world championship.