conscience

noun

1. (countable, uncountable)The ethical or moral sense of right and wrong, chiefly as it affects a person’s own behaviour and forms their attitude to their past actions.

   “Your conscience is your highest authority.”

   “1949, Albert Einstein, as quoted by Virgil Henshaw in Albert Einstein: Philosopher Scientist, Never do anything against conscience, even if the state demands it.”

   “As for Grierson, he poured liquor into himself as if it were so much soothing syrup, demonstrating that a good digestion is the highest form of good conscience.”

   “[“]Twer is not a friend of mine testifying against me reluctantly and for conscience’ sake, as the prosecution would have you believe. He is a spy, performing his paid job.[”]”

   “‘Then the father has a great fight with his terrible conscience,’ said Munday with granite seriousness. ‘Should he make a row with the police […]? Or should he say nothing about it and condone brutality for fear of appearing in the newspapers?”

2. (countable, uncountable)A personification of the moral sense of right and wrong, usually in the form of a person, a being or merely a voice that gives moral lessons and advices.
3. (countable, obsolete, uncountable)Consciousness; thinking; awareness, especially self-awareness.

   “Thus conscience does make cowards of us all; And thus the native hue of resolution Is sicklied o'er with the pale cast of thought.”