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duty; obligation
市民の安全を守るのは警察の責務である。
It is the duty of the police to protect the safety of citizens.
彼は自分の責務を全うするために全力を尽くした。
He did his best to fulfill his duties.
環境保護は企業が果たすべき社会的責務だ。
Environmental protection is a social responsibility that companies must fulfill.