Early 17th century; earliest use found in Alexander Richardson (fl. 1579–1629), logician. From ethic + -ian, after e.g. mathematician, physician; compare -ician.
Definition of ethician in US English:
ethician
noun
Ethicist.
Origin
Early 17th century; earliest use found in Alexander Richardson (fl. 1579–1629), logician. From ethic + -ian, after e.g. mathematician, physician; compare -ician.