- amoral (adj.)
- "ethically indifferent," 1882, a hybrid formed from Greek privative prefix a- "not" (see a- (3)) + moral, which is derived from Latin. First used by Robert Louis Stephenson (1850-1894) as a differentiation from immoral.
- ethical (adj.)
- c. 1600, "pertaining to morality," from ethic + -al (1). Related: Ethicality; ethically.
- unethical (adj.)
- 1871, from un- (1) "not" + ethical. Related: Unethically.