How to say "indefinite" in Japanese

• 不定ふていCommon
  no-adjective, na-adjectiveCovers 'indefinite' in the sense of not yet fixed or decided: a date, time, place, or number that has not been settled. It states this neutrally, without any hint of evasiveness.
• 頼りないたよりないCommon
  i-adjectiveAt heart this means unreliable or undependable; its 'indefinite' side is a reply or support so vague that you cannot rely on it. For 'indefinite' proper it is seldom the word you want.
• うやむやCommon
  na-adjective, nounDescribes matters or answers left hazy and unsettled, with a nuance of things being muddled or glossed over rather than simply unknown. Normally written in kana, it fits situations never clearly resolved.
  その問題もんだいをうやむやにしておくことはできない。↗

  We shouldn't leave the matter unsettled.
• 無期むきCommon
  no-adjectiveA term or period with no limit, but mostly seen inside set expressions; alone it is seldom how you say 'indefinite' — for an open-ended period use 無期限.
• 無期限むきげんCommon
  no-adjectiveLiterally 'without a time limit': the word for 'indefinite' when a span of time is meant — a period, extension, or suspension that has no set end. This is the choice for open-ended arrangements.
  組合くみあいは無期限むきげんストに入はいった。↗

  The union went out on a strike for an indefinite period.

Choose 不定 for things not yet fixed, such as dates or plans; 無期限 for periods with no time limit; 「うやむや」 for matters left vague or muddled; 「頼りない」 really means unreliable; 無期 appears chiefly in set expressions.

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

• 不定ふていunsettled
• 頼りないたよりないunreliable
• うやむやindefinite
• 無期むきindefinite
• 無期限むきげんindefinite
• あやふやuncertain
• 不確かふたしかunreliable
• 不確定ふかくていuncertain
• 不特定ふとくていunspecified
• 不徹底ふてっていinconsistent
• 不定形ふていけいundefined