How to say "indispensable" in Japanese

• 必須ひっすCommon
  no-adjective, na-adjectiveTreats the thing as a strict requirement: something that must be present, included, or done. Fits contexts like required items, conditions, or qualifications.
  堪能たんのうな英語力えいごりょくは必須ひっすです。↗

  Fluency in English is a must.
• 不可欠ふかけつJLPT N1approx.Common
  na-adjective, nounStresses that something cannot be done without; the word for saying one thing is indispensable to another, forming an essential part of it.
  自由じゆうこそ不可欠ふかけつなものだ。↗

  Freedom is the breath of life.
• マストCommon
  na-adjective, nounColloquial borrowing of 'must'; the casual 'must-have' word for things you simply have to get, do, or try, as in recommendations and advertising.
• 必要ひつようJLPT N4approx.Common
  na-adjectiveThe all-purpose word for 'necessary; needed'. When 'indispensable' amounts to 'needed', this neutral word is what you want; it states necessity without the emphatic force of 必須 or 不可欠.
  私達わたしたちが生いきていくためには衣食住いしょくじゅうが必要ひつようです。↗

  We need food, clothes and a home in order to live.
• 必携ひっけいCommon
  no-adjective, noun (suffix)Literally 'must be carried with you'; found chiefly in the titles of handbooks and guides meant as must-have companions. Seldom the word you want for 'indispensable' in ordinary sentences — use 必須 or 不可欠 there.
  TOEICの学習がくしゅうに限かぎらず、英語えいごを学まなぶのであれば英和えいわ辞典じてんは必携ひっけいの書しょの一ひとつでしょう。↗

  An English-Japanese dictionary is surely a must have book, not just for those taking TOEIC, but for all studying English.

Choose 必要 for plain 'needed'; 必須 or 不可欠 when something is truly essential, with 不可欠 especially for one thing being indispensable to another; 「マスト」 for casual 'must-have'; 必携 chiefly in guidebook titles.

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

• 必須ひっすindispensable
• 不可欠ふかけつindispensable
• マストnecessary
• 必要ひつようnecessary
• 必携ひっけいindispensable
• なくてはならないcannot do without something
• なくてはいけないcannot do without something
• なきゃいけないcannot do without something
• なくちゃいけないcannot do without something
• なくてはいけませんcannot do without something
• 欠かせないかかせないindispensable
• 欠くことのできないかくことのできないindispensable
• 欠くことができないかくことができないindispensable
• 欠くべからざるかくべからざるindispensable
• 必備ひつびindispensable
• なきゃならないcannot do without something
• 必要不可欠ひつようふかけつabsolutely essential