How to say "legitimacy" in Japanese

• 正腹せいふく
  nounA rare word for legitimacy in the sense of legitimate birth—descent from the lawful wife; for the legitimacy of a government or action it is not the word you want.
• レジティマシー
  nounThe borrowed form of the English word, covering legitimacy, lawfulness, and legality at once; it suits writing that invokes the English concept as such, such as the legitimacy of a government or regime.
• 正統性せいとうせい
  nounFor legitimacy as rightful authority—whether a government, ruler, or claim is rightful and accepted—this is the word to reach for; its second sense, orthodoxy, applies the same idea to doctrine and belief.
• 適法性てきほうせい
  nounLegality in the strict sense: whether an act or proceeding conforms to the requirements of the law; its legitimacy is the legal kind, not the rightfulness of a government.
• 合法性ごうほうせい
  nounLawfulness or legality—whether something is permitted under the law; its legitimacy is likewise the legal kind, so for the rightfulness of a government or doctrine turn to 正統性.

For the rightfulness of a government or doctrine choose 正統性; for conformity to law choose 合法性 or 適法性; 「レジティマシー」 is the borrowed term for the English concept; 正腹 is a rare word for legitimate birth.

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

• 正腹せいふくlegitimacy
• レジティマシーlegitimacy
• 正統性せいとうせいlegitimacy
• 適法性てきほうせいlegality
• 合法性ごうほうせいlawfulness
• 正当性せいとうせいlawfulness