じゃないと

じゃないと
expression
otherwise; unless it is; if not
informalcolloquialgrammatical
1. unless it is ~; if it isn't ~
Attaches to a noun or na-adjective to give a condition that must be met, with the consequence of not meeting it following. The casual contraction of ではないと.
大人(おとな)じゃないと入(はい)れない。
You can't go in unless you're an adult.
土曜日(どようび)じゃないと時間(じかん)が取(と)れません。
I can't find time unless it's a Saturday.
この仕事(しごと)は経験者(けいけんしゃ)じゃないと任(まか)せられないと部長(ぶちょう)が言(い)っている。
The manager says this job can only be entrusted to someone with experience.
2. otherwise; or else
Used alone at the start of a sentence to warn what will happen if the action just mentioned is not taken. Conversational equivalent of さもないと.
急(いそ)ごう。じゃないと間(ま)に合(あ)わない。
Let's hurry. Otherwise we won't make it.
傘(かさ)を持(も)っていきなよ。じゃないと濡(ぬ)れるよ。
Take an umbrella. Otherwise you'll get wet.
今日中(きょうじゅう)に返事(へんじ)をしたほうがいい。じゃないと相手(あいて)を待(ま)たせることになる。
You'd better reply today. Otherwise you'll end up keeping them waiting.

The contraction of ではないと. Casual: fine in conversation and messages, but ではないと or でないと is expected in writing.

Common patterns

Similar words

  • でないと: the same meaning in a more neutral register, usable in writing
  • じゃなければ: slightly more formal, and less pointed as a warning
  • そうしないと: refers back to an action rather than attaching to a noun

Related Words

Compare: でないと (the same meaning in a more neutral…)
Compare: そうしないと (refers back to an action rather…)
general
Added 2026.8.16 15:19 · Revised 2026.9.2 13:02
30500/30683_janaito