じゃあるまいし
You are not ~ so..., it isn't ~ so...
Structure
Verb + ん + じゃある(1) + まいし
Verb + わけ + じゃある(1) + まいし
(1) ではある、でもある
Explanation
The expression じゃ or ではあるまいし is used to mean 'it's not as if (A), so (B)', or 'you're not (A), so you shouldn't (B)'. It is frequently used to rebuke someone for behaving in a manner that is unfitting for them or the situation.
まい is an auxiliary verb that expresses negative conjecture, carrying a meaning similar to ないだろう. Therefore, the phrase is a combination of では, the う-Verb ある ('to be'), まい ('it's not as if'), and the particle し, which emphasizes a reason. Together, these parts literally mean 'because it's not like it is (A), therefore (B)'.
じゃあるまいし is placed after a noun, or after a phrase that has been turned into a noun with a particle like の.
- 時間がないわけではあるまいし、もう少し丁寧にやったらどう？It's not like you're out of time, so why don't you try being a little more careful?
- 腐るわけではあるまいし、一口ぐらいくれてもいいだろう。It's not like it's going to spoil, so you could at least give me a bite.
- プロじゃあるまいし、少しのミスぐらいで落ち込まなくてもいいんじゃない？You're not a pro, so there's no need to get so down about a few small mistakes, is there?
The clause that follows じゃあるまいし typically expresses the speaker's advice, complaint, or disagreement, often with a critical or exasperated nuance.
Examples
神様じゃあるまいし、たまには人に頼ったっていいんだよ。
You're not a god, so it's okay to rely on others once in a while.
動物じゃあるまいし、自分の部屋ぐらいちゃんと片付けなさい！
You're not an animal, so clean up your own room properly!
映画じゃあるまいし、暴力で何でも解決できるわけじゃないぞ。
This isn't a movie, so you can't just solve everything with violence.
もう新人でもあるまいし、もっと堂々としていなさい。
You are not a rookie anymore, so act with more confidence!
これくらいの失敗で死ぬわけじゃあるまいし、そんなに慌てないで。
It's not like you'll die from a small mistake like this, so don't panic so much.
Ａ：「ニンジンは嫌いだ。食べない。」
Ｂ：「王様でもあるまいし、好き嫌いばかり言うのはやめなさい。」
A: 'I hate carrots. I'm not eating them.'
B: 'You're not a king, so stop being so picky!'
Ａ：「暑い！もうだめだ！」
Ｂ：「ここは南極じゃあるまいし、夏なんだから暑いのは当然だろう。」
A: 'It's so hot! I can't take it!'
B: 'This isn't Antarctica, so of course it's going to be hot in the summer.'
一人で何もできないわけじゃあるまいし、そろそろ親から自立したらどうだ。
It's not like you can't do anything by yourself, so how about becoming a little more independent from your parents?
江戸時代じゃあるまいし、一つの会社に一生を捧げる必要はないよ。
This isn't the Edo period, so there's no need to dedicate your entire life to one company.
もう大学生じゃあるまいし、自分のことばかり考えるのはやめなさい。
You're not a university student anymore, so stop thinking only about yourself.
宝くじが当たるわけじゃあるまいし、もっとちゃんとお金の計画を立てるべきだ。
It's not like you're going to win the lottery, so you should plan your finances more carefully.
戦国時代じゃあるまいし、たった10分歩くくらいで文句を言うな。
This isn't the Warring States period, so don't complain about a simple 10-minute walk.