いかんによらず

1. 1Irrespective of the state, content, or outcome of N; the result does not depend on it.Ex. 1
2. 2Whatever the outcome of N may be, the stated fact or value still holds.Ex. 2

A stiff, formal expression found in announcements, rules, official notices, and formal speech. It is a more formal counterpart of にかかわらず or によらず, with いかん adding the idea of the noun's changing state or outcome. The nouns it takes typically imply variation or a possible result, such as 天候, 結果, 合否, or 理由.

• 1.
  にかかわらずN2「にかかわらず」 has the same meaning; when attaching to nouns like 「天候」 or 「結果」, the two are often interchangeable, and it sounds less stiff. It can also attach to paired affirmative/negative forms such as 「行く行かない」 and 「〜か〜ないか」, whereas 「いかんによらず」 attaches only to nouns.
• 2.
  によらずN1「によらず」 attaches directly to nouns, often category nouns such as 「性別」 or 「年齢」, and it can also express not relying on a particular means, as in 「武力によらず」. 「いかんによらず」 usually attaches to a noun plus 「の」, focuses on how the situation or result turns out, and sounds stiffer.
• 3.
  を問わずN2「を問わず」 is similar in meaning, and the two are interchangeable when attaching to nouns like 「天候」. It attaches directly to nouns without 「の」, can also take antonym pairs like 「男女」 or forms like 「〜の有無」, and sounds less stiff than 「いかんによらず」.
• 4.
  いかんでは / いかんによってはN1「いかんでは / いかんによっては」 means “depending on ~, it is possible that ~”; the preceding element determines the outcome, which is the exact opposite of 「いかんによらず」, so the two cannot be interchanged. Both attach to nouns (「の」 may be added), and both are written-language forms.
• 5.
  であれ / であろうとN1「であれ」 attaches directly to nouns, な-adjective stems, or 「誰・何・どんな＋名詞」, while 「いかんによらず」 must attach to nouns (usually with 「の」). 「理由のいかんによらず」 ≈ 「理由が何であれ」.
• 6.
  にしろ / にせよN2「にしろ／にせよ」 can attach to nouns, verbs, and adjectives, expressing concession (“even if ~, still ~”) or listing concrete options as in 「AにしろBにしろ」. 「いかんによらず」 attaches only to nouns that encompass multiple possibilities, sounds stiffer, and the two cannot be directly interchanged.

にかかわらず, によらず, and を問わず also mean 'regardless of', but they are less formal and lack いかん's focus on the noun's varying state or outcome, while いかんでは / いかんによっては means the opposite: 'depending on N', so the result may change. であれ / であろうと and にしろ / にせよ are concessive 'even if / whether X or Y' forms that attach more flexibly and often list alternatives, unlike this fixed formal noun pattern.