Refers to people who serve a monarch or lord; a historical term not used in everyday modern Japanese. Often appears in discussions of feudal or imperial systems.
The word 人臣 is a historical expression referring to those who serve a monarch.
Compound of 人 (person) and 臣 (retainer, subject). The exact historical derivation is uncertain, but the kanji combination directly conveys the meaning of a person in a subordinate role to a ruler.