Where does “морали́ст” come from?

морали́ст (Russian) comes from French moraliste, from Latin mōrālis, from Latin -ālis, from Proto-Italic -ālis.

Ancestry of “морали́ст”, step by step

Step	Language	Word	Meaning
1	French	moraliste	moralist
2	Latin	mōrālis	—
3	Latin	-ālis	—
4	Proto-Italic	-ālis	—

морали́ст — Etymology, Origin & Word History | Etymology Explorer