明(あ)かす

あかす
verb (godan)
to reveal, to disclose; to spend (the night)
1. to reveal, to disclose, to confess
To make something hidden or secret known. Often used for revealing one's identity, a secret, or the truth.
秘密(ひみつ)を明(あ)かした。
I revealed the secret.
彼(かれ)は自分(じぶん)の正体(しょうたい)を明(あ)かさなかった。
He did not reveal his true identity.
長年(ながねん)隠(かく)していた過去(かこ)を友人(ゆうじん)に明(あ)かす決心(けっしん)をした。
I decided to reveal to my friend the past I had hidden for years.
2. to spend (the night), to stay up all night
To pass the night doing something. Often used in the pattern 〜明(あ)かす to mean spending the entire night engaged in an activity.
一晩(ひとばん)語(かた)り明(あ)かした。
We talked through the entire night.
試験(しけん)勉強(べんきょう)で夜(よる)を明(あ)かした。
I stayed up all night studying for the exam.
友人(ゆうじん)と飲(の)み明(あ)かして、朝(あさ)まで帰(かえ)れなかった。
I drank through the night with a friend and couldn't go home until morning.

TRANSITIVITY: 他動詞(たどうし) (transitive).

USAGE:
Sense 1 takes を to mark what is revealed: 秘密(ひみつ)を明(あ)かす, 正体(しょうたい)を明(あ)かす.
Sense 2 is often used as a compound verb suffix: V連用形(れんようけい) + 明(あ)かす (e.g., 語(かた)り明(あ)かす, 飲(の)み明(あ)かす). Also used as 夜(よる)を明(あ)かす (to spend the whole night).

COMMON COLLOCATIONS:

  • 秘密(ひみつ)を明(あ)かす: to reveal a secret
  • 正体(しょうたい)を明(あ)かす: to reveal one's identity
  • 夜(よる)を明(あ)かす: to stay up all night
  • 語(かた)り明(あ)かす: to talk all night long
  • 飲(の)み明(あ)かす: to drink all night long

SIMILAR WORDS:

  • 暴(あば)く: to expose, to uncover (forceful)
  • 打(う)ち明(あ)ける: to confide, to open up about
general
Added 2026.2.23 8:40
12500/12961_akasu