主君|しゅくんshukun[1]atamadaka (head-high)

1. nounlord; master

• Synonym主あるじNeutral「主（あるじ）」: the head of a household or a shopkeeper. A general word for 'master', used in speech and writing alike, not limited to the lord a samurai serves.
• Synonym主人しゅじんNeutral「主人」 is a broad word for the head of a household or a shopkeeper, in speech or writing; unlike 「主君」, it does not single out the lord one serves.
• Synonym殿様とのさまNeutralAn honorific for a daimyo, like 'my lord'; it can also be used mockingly of a man ignorant of the ways of the world.
• Synonym主公しゅこうWrittenWritten and rare: one's lord, as with 「主君」, but it can also mean the protagonist of a work, and it is less common than 「主君」.
• Related君主くんしゅFormalFormal: the supreme ruler of a state. 「主君」 views things from the retainer's side, naming the lord one serves.
• Related雇い主やといぬしNeutralA modern word for an employer; it is about the employment relationship, with none of the lord-vassal loyalty implied by 「主君」.
• Related領主りょうしゅWrittenWritten: a feudal lord, with the emphasis on holding and ruling land, not on the personal lord-retainer bond that 「主君」 implies.
• Antonym家臣かしんWrittenA written word for a retainer serving a lord — the very opposite of 「主君」, the one who is served.
• Antonym臣下しんかFormalFormal and written: one who submits to and serves a monarch — the counterpart of 「主君」, who gives the commands.

Use 「主君」 for the lord whom retainers serve, chiefly in historical drama. For a nation's supreme ruler, say 「君主」; to address a daimyo respectfully, 「殿様」. The opposite of 「主君」 is 「家臣」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 家臣かしんたちが従したがう人物じんぶつ。