未定|みていmitei[0]heiban (flat)

1. no-adjective, na-adjectivenot yet fixed; undecided; pending; TBD
   計画けいかくはまだ未定みていである。↗

   The plans are still up in the air.

• Synonym不定ふていWrittenWritten style: means not fixed or irregular, as in 「住所不定」. 「未定」 suggests the matter will be settled later.
• Synonym不確定ふかくていWrittenWritten and academic, as in 「不確定性」: uncertain, unable to be pinned down. 「未定」 covers schedules, policies or personnel matters not yet decided.
• Related未解決みかいけつNeutralUsed for problems that remain unsolved; the focus is on the problem itself. 「未定」 is about dates, candidates or plans not yet being decided.
• RelatedうやむやNeutralHandled vaguely so a matter is left to fizzle out; carries a negative shade. 「未定」 is an objective state of awaiting a decision.
• Related不定ふていWrittenWritten style: means not fixed or irregular, as in 「住所不定」. 「未定」 suggests the matter will be settled later.
• Related不明ふめいNeutralMeans unclear or unknown, as in 「原因不明」. 「未定」 is about something not yet decided, not something unknowable.
• Related不確実ふかくじつWrittenWritten style: uncertain and unreliable, with an emphasis on risk. 「未定」 stresses only that a decision is still pending.
• Related不確かふたしかNeutralSuggests something shaky or unreliable, not to be counted on. 「未定」 is simply an objective state of awaiting a decision.
• RelatedあやふやNeutralVague and hard to pin down; leans colloquial. 「未定」 is the formal way to say a decision is still pending.
• Related宙ぶらりんちゅうぶらりんCasualColloquial: describes something left hanging in midair, with a sense of awkward limbo. 「未定」 simply and objectively says no decision has been made.
• Related未確定みかくていWrittenFormal, officialese flavor: not yet confirmed or determined. 「未定」 is more common and more concise.
• Related未決定みけっていWrittenWritten style: no decision has been made yet. 「未定」 is the shorter, more everyday choice.
• Antonym確定かくていNeutralAntonym: the matter has been fixed or confirmed — the opposite of 「未定」, which is still undecided.
• Antonym既定きていWrittenWritten antonym: already established or predetermined, as in 「既定方針」 — the reverse of 「未定」.
• Antonym決定けっていNeutralAntonym: a decision has been made, where 「未定」 still awaits one.

Use 「未定」 for dates, candidates or plans not yet decided, as in 「日時未定」. For an unsolved problem say 「未解決」; for something left hanging, 「宙ぶらりん」; for a matter left to fizzle out, 「うやむや」. 「不確実」「不確か」「不確定」 stress uncertainty or risk rather than a pending decision; 「未確定」「未決定」 are stiffer written equivalents. Antonyms: 「確定」「既定」 for what is already fixed, 「決定」 for the decision itself.

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

1. まだ定さだまっていないこと。