元凶・元兇|げんきょうgenkyou[0]heiban (flat)

1. nounringleader; main culprit
2. nounmain cause; source

• Synonym張本人ちょうほんにんNeutralPoints to the person who originated an incident, stressing the one mainly responsible; slightly milder in tone and more colloquial than 「元凶」.
• Related根源こんげんNeutralMeans the root cause and leans abstract, as in 「諸悪の根源」; 「元凶」 is more figurative for the culprit behind a bad result.
• Related本元ほんもとNeutralRefers to the origin or authentic source, often as 「本家本元」; neutral and carries no sense of guilt.
• Antonym救世主きゅうせいしゅNeutralA saviour who rescues people from hardship — the opposite of 「元凶」, which brings harm.

Use 「元凶」 for the culprit or ringleader behind a bad outcome, as in 「肥満の元凶」「事件の元凶」. For the originator of an incident say 「張本人」, for the root cause 「根源」; the opposite is 「救世主」.

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

1. 悪事あくじを企くわだてた中心人物ちゅうしんじんぶつ。
2. 悪わるい状況じょうきょうを引き起ひきおこした根源こんげん。