いけない

ikenai

adjective★Intermediate

informal

Not allowed; forbidden

ここに入ってはいけない

You must not enter here

💡

Often used to express prohibition or warning

informal

Bad; naughty (when referring to children's behavior)

子供がいけないことをした

The child did something bad

💡

Used in a more casual or affectionate way when talking about children

informal

Not good; problematic

この状況はいけない

This situation is not good

💡

Used to express concern or dissatisfaction

いけないことbad thingいけない子naughty child

いけないよphrase

You shouldn't (casual warning)

The meaning of 'いけない' changes drastically based on context. Pay attention to the situation and tone when using or interpreting it.

Always carries a negative or prohibitive meaning, whether literal or figurative.

Derived from the verb '行く' (to go) with the negative form 'いけない' (must not go), later extended to mean 'not allowed' or 'bad'

The meaning can vary significantly depending on context and tone. Often used in parenting or casual conversation.

いけ

must not (from '行く' in negative form)

root

ない

negative suffix

suffix

✎ Noted on May 2, 2026JA → EN