良心 (liáng xīn): lương tâm

He found a wallet full of cash. Although no one was watching, his conscience told him he had to return it to its owner.

This company added harmful substances to food in order to make money. They really have no conscience and should be severely punished by law.

Seeing that children in the disaster area lacked food and clothing, his conscience troubled him, and he immediately donated a large sum of money.

It is unconscionable for a doctor to conceal a patient's condition; the patient has the right to know their own health status.

He has always done business according to his conscience and never cheats customers, so everyone trusts him.