moralist
/mɔːrˈælɪst/Definitions
1. noun
a person who holds a particular set of moral principles and teaches or advocates them, often in a forceful or didactic manner
“The writer was known as a moralist for her strong views on social justice.”
2. noun
a person who is guided by a strong sense of what is right and wrong
“As a moralist, he always tried to do the right thing, even if it was difficult.”