A general law or rule adopted or professed as a guide to action; a settled ground or basis of conduct or practice; a fundamental motive or reason…

With plural agreement. Moral principles; maxims, precepts, or observations concerning these.

In singular. A person's moral beliefs or principles. Cf. morality, n. 5c. Obsolete.

The morals or morality of a person or group of people; moral principles or conduct. Now rare.

In plural. Principles of acceptable conduct or behaviour, informed by ideas of morality, decency, etc. Often in high standards, low standards.