〜じゃあるまいし
JLPT N1:you are not X, so
Rejects an excuse or behavior because the person or situation is not X: “you aren't X, so…”. It is casual and often critical.
How to form it
- Put a noun before じゃあるまいし: 子供じゃあるまいし.
- ではあるまいし is the more formal version. でもあるまいし can follow a phrase such as 初めてのこと.
- The following clause states what should be obvious given that X is false.
Examples
子供じゃあるまいし、自分のことは自分でしなさい。
You are not a child, so take care of your own affairs.
初めてのことでもあるまいし、そんなに緊張する必要はない。
It is not your first time, so there is no need to be that nervous.
Common mistakes
- Using it as a neutral factual negation.
- Leaving out the implied expectation or criticism.