明かす|あかすakasu[0]heiban (flat)

JLPT N1approx.Common
Definitions
  1. godan verb, transitive verbto pass (the night); to spend
    彼かれは寝ねずに一夜いちやを明あかした。↗
    He sat up all night.
  2. godan verb, transitive verbto reveal; to divulge; to disclose; to expose
    これは秘密ひみつです。他人たにんに明あかさないでください。↗
    This is a secret. Keep it to yourself.
  3. godan verb, transitive verbto prove; to verify
Conjugation
Dictionary form明かす(あかす)
Polite (masu)明かします(あかします)
Negative (nai)明かさない(あかさない)
polite (masen)明かしません(あかしません)
classical zu / nu明かさず・明かさぬ(あかさず・あかさぬ)
Past (ta)明かした(あかした)
polite (mashita)明かしました(あかしました)
Past negative (nakatta)明かさなかった(あかさなかった)
polite (masen deshita)明かしませんでした(あかしませんでした)
Te form明かして(あかして)
Potential明かせる(あかせる)
Passive明かされる(あかされる)
Causative明かさせる(あかさせる)
Causative passive明かさせられる(あかさせられる)
Conditional (ba)明かせば(あかせば)
tara明かしたら(あかしたら)
Volitional明かそう(あかそう)
polite (mashou)明かしましょう(あかしましょう)
Imperative明かせ(あかせ)

Common forms generated by rule; see the senses for honorific or irregular usage.

Transitive / intransitive pair
transitive明かすあかす⇄intransitive明けるあける
夜よるが明あける
夜よるを明あかす
夜が明ける describes dawn breaking naturally, while 夜を明かす describes someone actively staying up through the night.

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

Synonyms & antonyms
  • Synonym過ごすすごすNeutralSpends or passes time, as in 「休日を過ごす」; it covers everyday time-passing, while 「明かす」 in this sense only means staying up through the night.
  • Synonym打ち明けるうちあけるNeutralMeans confiding secrets or worries, as in 「悩みを打ち明ける」; close to the revealing sense of 「明かす」 but with a stronger nuance of opening one's heart.
  • Related暮らすくらすNeutralMeans living or getting by, as in 「田舎で暮らす」; it suggests long-term everyday life rather than a single night.
  • Antonym隠すかくすNeutralMeans to hide or conceal, standing opposite 「明かす」 in its sense of revealing the truth.
  • Antonym秘めるひめるWrittenWritten style; means keeping something hidden within, as in 「思いを胸に秘める」; the opposite of 「明かす」.

Use 「明かす」 for revealing secrets or truths and for staying up through the night, as in 「秘密を明かす」 and 「夜を明かす」. For confiding worries say 「打ち明ける」, for spending time 「過ごす」; the opposites are 「隠す」 and 「秘める」.

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

Japanese definitions
  1. 明あきらかにする。明あかるみに出だす。うちあける。
  2. (「証しょうす」とも)証明しょうめいする。
  3. 徹夜てつやして朝あさを迎むかえる。
Kanji in this word
English equivalents
See also

JLPT vocabulary levels are community estimates, not official (no official lists have been published since the 2010 revision).

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