How to say "assertion" in Japanese

• 主張しゅちょうJLPT N3approx.Common
  noun, suru verb, transitive verbCovers 'assertion' in the sense of a claim or position that one maintains and argues for; the nuance is insistence, putting one's own view forward and standing by it.
  私わたしたちはその重要性じゅうようせいを主張しゅちょうした。↗

  We insisted on its importance.
• 断言だんげんJLPT N1approx.Common
  noun, suru verb, transitive verbThe word for asserting something flatly and with full confidence, leaving no room for doubt; use it when 'assertion' means a definite statement that something is or is not the case.
  私は彼かれが潔白けっぱくだと断言だんげんした。↗

  I affirmed that he was innocent.
• 言明げんめいCommon
  noun, suru verb, transitive verbSuits 'assertion' as an explicit statement made in words, declaring a position or intention clearly; closer to 'declaration' or 'statement' than to the arguing of a claim.
  「わたしはキリストではありません」と言明げんめいした。↗

  But confessed freely, I am not the Christ.
• 表明ひょうめいCommon
  noun, suru verb, transitive verbReally means making one's attitude, stance, or intention known outwardly — a declaration or manifestation rather than an assertion; seldom the word you want for asserting a claim.
  あなたがこの町まちにしてくれた事ことに対たいして心こころからの感謝かんしゃを表明ひょうめいします。↗

  I express my cordial thanks for what you have done for this city.

Use 主張 for a claim or position you argue for, 断言 for a confident, flat assertion that something is true, 言明 for an explicit formal statement, and 表明 for declaring a stance or intention rather than asserting a claim.

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

• 主張しゅちょうclaim
• 断言だんげんassertion
• 言明げんめいdeclaration
• 表明ひょうめいdeclaration
• アサーションassertion
• 確言かくげんassertion
• 言い切りいいきりaffirmation
• 提題ていだいthesis (of an argument)