不定(ふてい)

ふてい
noun, na-adjective
indefinite; uncertain; irregular
formalabstract
1. indefinite; uncertain; not fixed; irregular
The state of not being determined, fixed, or regular. Used in both everyday and technical contexts including grammar and mathematics.
出発(しゅっぱつ)日(び)は不定(ふてい)だ。
The departure date is undecided.
不定期(ふていき)に発行(はっこう)される雑誌(ざっし)だ。
It's a magazine published at irregular intervals.
英語(えいご)の不定(ふてい)冠詞(かんし)は a と an の二(ふた)つがある。
There are two indefinite articles in English: 'a' and 'an'.

Composed of 不(ふ) (not, un-) + 定(てい) (fixed, determined). A versatile prefix-like word that appears in many compounds across different fields.

Common collocations

  • 不定期(ふていき): irregular, at irregular intervals
  • 不定(ふてい)冠詞(かんし): indefinite article (grammar)
  • 不定(ふてい)形(けい): infinitive form (grammar)
  • 不定(ふてい)愁訴(しゅうそ): vague complaints (medical: nonspecific symptoms)
  • 住所(じゅうしょ)不定(ふてい): of no fixed address

Similar words

Related Words

Compare: 未定(みてい) (undecided, not yet decided)
Compare: 不確定(ふかくてい) (uncertain, undetermined)
Antonym: 一定(いってい) (fixed, constant)
general
Added 2026.4.8 4:16 · Revised 2026.9.2 13:02
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