いけない

expression, i-adjective

bad; wrong; naughty

Used to describe behavior or situations that are morally or socially unacceptable. Often used when scolding children or expressing disapproval.

• そんなことをしてはいけません。

  You mustn't do such a thing.

• うそをつくのはいけないことだ。

  Telling lies is wrong.

expression, i-adjective

must not; should not; ought not to

Attaches to the -te form of a verb or adjective to express prohibition or strong advice against doing something.

• ここで写しゃ真しんを撮とってはいけません。

  You must not take photos here.

• 遅おくれてはいけないから、早はやく出でよう。

  We shouldn't be late, so let's leave early.

expression, i-adjective

no good; useless; hopeless

Expresses that something is not working, not acceptable, or beyond repair. Sense 4 (hopeless) is a stronger extension of this meaning.

• このパソコン、もういけないみたい。

  This computer seems to be no good anymore.

• 彼かれに頼たのんでもいけないよ。

  It's no use asking him.

expression, i-adjective

unfortunate; a shame; a pity

Used to express sympathy or regret about a situation. Often appears as いけないね or いけないことになった.

• 雨あめで運うん動どう会かいが中ちゅう止しだって。いけないね。

  The sports day was canceled because of rain. That's a shame.

expression, i-adjective

unable to drink (alcohol)

Specifically refers to being unable to handle alcohol; a set expression often used as お酒がいけない.

• 私わたしはお酒さけがいけないんです。

  I can't drink alcohol.

expression, i-adjective

so as not to ...; lest ...; in case ...

Used in the pattern ...すると/してはいけないから/ので to express doing something to prevent an undesirable outcome.

• 忘わすれないようにメモしておこう。いけないからね。

  Let's write it down so we don't forget. Just in case.