How to say "plaintiff" in Japanese

• 原告げんこくCommon
  nounThe common word for the plaintiff in a lawsuit: the party who brings the case against the defendant. When 'plaintiff' means the person suing, this is the word to reach for first.
  裁判官さいばんかんは原告げんこくに不利ふりな判決はんけつを下くだした。↗

  The judge decided against the plaintiff.
• 原告側げんこくがわ
  noun原告 plus 側 'side': the plaintiff's side or party in a case, rather than an individual plaintiff. Less common than 原告, it emphasizes the side taken in the suit.
• 告発者こくはつしゃ
  nounReally 'accuser, denouncer': a person who exposes or accuses someone of wrongdoing, often publicly or to the authorities. It fits 'complainant' better than 'plaintiff' and is seldom the word for a civil-suit plaintiff.
• 告訴人こくそにん
  nounA person who files a formal criminal complaint against another. It belongs to criminal procedure, so it suits the 'complainant' sense and is not the word for the plaintiff in a civil lawsuit.
• 訴訟人そしょうにん
  nounPrimarily 'litigant': a party to a lawsuit, on either side. It does not specify which party, so it is an imprecise rendering of 'plaintiff' — use it when 'litigant' is what you mean.

Use 原告 for the plaintiff in a lawsuit; 原告側 for the plaintiff's side; 告訴人 for the filer of a criminal complaint; 告発者 for an accuser or denouncer; 訴訟人 means litigant, either party to a suit.

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

• 原告げんこくplaintiff
• 原告側げんこくがわplaintiff
• 告発者こくはつしゃcomplainant
• 告訴人こくそにんcomplainant
• 訴訟人そしょうにんlitigant
• 甲こうthe A party (e.g. in a contract)