1610s, "a person's moral qualities," plural of moral (n.). Meaning "conduct, behavior, course of life in regard to right and wrong," often specifically with regard to sexual conduct, is by 1690s.
Entries linking to morals
moral n.
"moral exposition of a story, the doctrine inculcated by a fable or fiction, the practical lesson which anything is designed to teach," c. 1500, from moral (adj.) and from French moral and Medieval Latin moralia. In this sense, morality was used from late 14c. The earlier noun use of moral was "a commandment pertaining to morals."