Japatan
Formation
- N + ではあるまいし
- N + じゃあるまいし(話し言葉)
- V普通形 + の / わけ + ではあるまいし
Explanation
Means "since it's not as if ~." The speaker mentions something that is obviously not the case, as in "you're not a child," to criticize or advise someone. It is followed by the speaker's judgment, advice, or command. In speech, 〜じゃあるまいし is common.
Examples
子どもじゃあるまいし、自分のことは自分でやりなさい。
You're not a child, so take care of your own things.
新入社員ではあるまいし、そんな基本的なことを聞かないでくれ。
You're not a new employee, so don't ask me such basic things.
二度と会えないわけではあるまいし、そんなに泣かないで。
It's not as if we'll never see each other again, so don't cry so much.
観光に来たのではあるまいし、出張中にお土産ばかり買っていてはだめだよ。
You didn't come here for sightseeing, so you shouldn't be buying souvenirs all the time during a business trip.
Notes
This sounds somewhat harsh and can be rude to superiors. The first part is something obviously untrue, and the second part is the speaker's opinion or advice, not a neutral fact.
Mini quiz
1魔法使い（ ）、そんなにすぐには直せませんよ。
Answer and explanation
Answer: 2 じゃあるまいし
"I'm not a magician, so I can't fix it that quickly." じゃあるまいし means "it's not as if I were ~." The other choices do not make sense here.
2二度と会えない（ ）、そんなに悲しまないで。
Answer and explanation
Answer: 1 わけではあるまいし
"It's not as if we'll never meet again, so don't be so sad." わけではあるまいし fits. The other choices do not match the meaning, and ばこそ cannot follow ない this way.
3「ではあるまいし」の使い方が正しいものはどれか。
Answer and explanation
Answer: 3 小学生ではあるまいし、電車の乗り方くらい自分で調べなさい。
Sentence 3 means "You're not an elementary school kid, so look up how to take the train yourself." The others have no advice or criticism after ではあるまいし, so they are wrong.
