moral compass

Meanings

1. An inner sense which distinguishes what is right from what is wrong, functioning as a guide for morally appropriate behaviour.
2. A belief system, person, etc. serving as a guide for morally appropriate behaviour.
3. The full range of actions, vices, or virtues, which may affect others and which are available as choices to a person, group, or people in general.

Etymology

From moral (“of or relating to principles of right and wrong in behaviour; conforming to a standard of right behaviour”) + compass (“device used to determine the cardinal directions”), from the fact that a compass indicates various directions on its face (sense 3), and enables its user to find the correct direction to go in (sense 1).