From Latin 'moralis,' coined by Cicero as a Latin equivalent of Greek 'ethikos,' from 'mos' (custom, character).
Relating to principles of right and wrong in behavior; concerned with the goodness or badness of human character or conduct.
From Latin moralis (of manner, custom, or character), coined by Cicero as a translation of Greek ethikos (ethical), from mos, moris (custom, habit, usage, manner, law). The PIE root *me- (to measure, to think) lies behind several Latin words relating to established practice. Cicero needed a Latin equivalent for Aristotle concept of ethos — the character formed
Cicero explicitly invented 'mōrālis' as a Latin translation of the Greek 'ēthikos,' making it one of the few major philosophical terms whose exact moment of coinage is documented — he announced the neologism in his work 'De Fato' around 44 BCE.