確固・確乎|かっこkakko[1]atamadaka (head-high)

1. taru-adjective, adverb (with と)firm; unshakeable; resolute
   いずれの会社かいしゃにも確固かっこたる事業じぎょう計画けいかくがある。↗

   Every company has a firm business plan.

• Synonym断固だんこWrittenA written word modifying actions and attitudes, as in 「断固反対」 and 「断固として拒否する」; it stresses decisive resolve, while 「確固」 stresses unshakeable beliefs or standing.
• Synonym断然だんぜんNeutralAn adverb for acting decisively or flatly, and for being far ahead, as in 「断然有利」; 「確固」 usually appears as 「確固たる」 before a noun to describe firmness.
• RelatedしっかりNeutralUsually written 「しっかり」; the most common everyday word for gripping tightly, being dependable, or doing things properly; 「確固」 is a written word for beliefs and standing.
• RelatedがっしりNeutralA mimetic word for a sturdy build or solid structure, stressing physical firmness; 「確固」 applies to abstract things such as beliefs and standing.
• RelatedしかとWrittenA written adverb with an old-fashioned flavor, meaning certainly or clearly, as in 「しかと見届ける」; 「確固」 describes firm beliefs or foundations and does not express clarity.
• Related牢としてろうとしてWrittenRare even in written prose; it means firmly and mostly appears as 「牢として動かない」, so in everyday use 「確固たる」 or 「しっかり」 is enough.
• Antonym曖昧あいまいNeutralMeans vague or ambiguous, as in 「曖昧な態度」; the opposite of 「確固」, which suggests a clear-cut, unshakeable stance.
• Antonym不確かふたしかNeutralMeans uncertain or unreliable, as in 「不確かな情報」; the opposite of 「確固」, which is firm and dependable, never wavering.

Use 「確固たる」 for unshakeable beliefs, standing, or grounds. For resolute action pick 「断固」; in everyday speech 「しっかり」 covers holding firm. The opposites are 「曖昧」 and 「不確か」.

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

1. しっかりして確たしかなこと。