1.
conscience, moral sense
The inner sense of right and wrong that guides a person's actions. Used similarly to the English word "conscience" in both everyday and formal contexts.
Usage
Note the homophone 両親 (parents) — context usually makes the distinction clear.
良心 is used in similar expressions as English "conscience": it can ache (痛む), prick (咎める), or cause torment (呵責). The expression 良心的 (conscientious) is commonly used to describe fair pricing or honest business practices.