暴君|ぼうくんboukun[1]atamadaka (head-high)

1. nountyrant; despot
   このようにして、暴君ぼうくんはその王国おうこくの征服せいふくに成功せいこうした。↗

   Thus, the tyrant succeeded in conquering the kingdom.

• Synonym専制君主せんせいくんしゅWrittenWritten term for a monarch who rules autocratically; it stresses the absolutist system of government rather than cruelty, so not every 専制君主 is a 暴君.
• Synonym独裁者どくさいしゃNeutralNeutral word, common in everyday news; stresses holding absolute power and covers any dictator, not just a monarch.
• Synonym圧制者あっせいしゃWrittenWritten but rare; stresses oppressing the people through brute power — about oppression itself rather than monarchy.
• RelatedタイラントWrittenWritten loanword, rare in prose; mostly appears as names or characters in games and fiction.
• Antonym名君めいくんWrittenWritten term for a wise ruler whose reign sets an example — the exact opposite of a 暴君 who governs by tyranny.
• Antonym仁君じんくんWrittenWritten term for a benevolent, kindly monarch, standing opposite the cruel, overbearing 暴君.

Use 「暴君」 for a cruel, tyrannical monarch (also figuratively for a tyrant at home). For autocratic rule as a system choose 「専制君主」; for modern dictators in the news, 「独裁者」. The opposite of a 暴君 is a 「名君」.

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

1. 治世ちせいにおいて、圧政あっせいを行おこなうなど、乱暴らんぼうなふるまいを行おこなった君主くんしゅ。