noun
strong arm; powerful arm
Literally a physically strong or stout arm; often used in contexts of physical strength or sports.
彼の剛腕から投げられたボールは速かった。
The ball thrown from his powerful arm was fast.
noun, noun which may take the genitive case particle 'no'
capable person; strong leader; ability to get things done
Figurative use: a person with strong leadership or the ability to push through difficult tasks; often used in business or political contexts.
新社長は剛腕で知られ、改革を次々と実行した。
The new president is known for being a strong leader and carried out reforms one after another.
彼の剛腕ぶりには誰も逆らえない。
No one can oppose his forceful way of doing things.
Compound of 剛 (strong, firm) or 豪 (powerful, heroic) and 腕 (arm). The figurative sense likely developed from the image of a strong arm that can accomplish difficult tasks.