noun
obligation to make a sincere effort
A legal or regulatory duty to try one's best, rather than a strict obligation to achieve a specific result. Common in Japanese law and guidelines.
この法律では、事業者に安全対策の努力義務が課されている。
Under this law, businesses have an obligation to make a sincere effort regarding safety measures.
努力
Just because it's an obligation to make an effort doesn't mean you can do nothing.
Compound of 努力 (effort) and 義務 (obligation). A modern legal term.