Meaning & Usage
✨ Basic Meaning
Should not / Must not / Ought not to.
🎯 Primary Function
To express moral obligation, social duty, or strong logical recommendation against an action.
📋 Grammar Structure
Verb (Dictionary Form) + べきではない (Note: する becomes すべき or するべき)
[I-Adjective] + くある + べきではない (rarely used)
[Na-Adjective] + である + べきではない (rarely used)
The form itself is the negative of べきだ.
🎭 Usage Contexts
Formal Situations
Used in speeches, formal writing, and business settings to state rules or standards of behavior.
Informal Situations
Used among friends or family when giving serious advice, though it can sound a bit ‘preachy’ or strong.
Written Language
Very common in essays, editorials, and instructional manuals.
Spoken Language
Common in serious discussions, debates, or when correcting someone’s behavior.
💡 Common Applications
Social Ethics
Expressing what is considered inappropriate behavior in society.
Example: 電車の中で騒ぐべきではない。
Strong Advice
Giving firm advice based on logic or common sense rather than personal feelings.
Example: 健康のために、夜更かしをすべきではない。
Regret (Past Tense)
Using the past tense ‘beki de wa nakatta’ to express regret about a past action.
Example: あんなことを言うべきではなかった。
Frequency
High
Difficulty
N3
Tag:
Example Sentences
Example #1
そんなことを人に言うべきではない。
Furigana: そんなことをひとにいうべきではない。
Romaji: Sonna koto o hito ni iu beki de wa nai.
English: You shouldn’t say such things to others.
Example #2
嘘をつくべきではない。
Furigana: うそをつくべきではない。
Romaji: Uso o tsuku beki de wa nai.
English: You shouldn’t tell lies.
Example #3
図書館で大声で騒ぐべきではない。
Furigana: としょかんでおおごえでさわぐべきではない。
Romaji: Toshokan de oogoe de sawagu beki de wa nai.
English: One shouldn’t make a loud noise in the library.
Example #4
他人の意見を無視すべきではない。
Furigana: たにんのいけんをむしすべきではない。
Romaji: Tanin no iken o mushi subeki de wa nai.
English: You shouldn’t ignore other people’s opinions.
Example #5
食べ物を無駄にすべきではない。
Furigana: たべものをむだにすべきではない。
Romaji: Tabemono o muda ni subeki de wa nai.
English: We shouldn’t waste food.
Example #6
大事な決断を急ぐべきではない。
Furigana: だいじなけつだんをいそぐべきではない。
Romaji: Daiji na ketsudan o isogu beki de wa nai.
English: You shouldn’t make important decisions in a hurry.
Example #7
両親への感謝を忘れるべきではない。
Furigana: りょうしんへのかんしゃをわすれるべきではない。
Romaji: Ryoushin e no kansha o wasureru beki de wa nai.
English: You shouldn’t forget your gratitude toward your parents.
Example #8
一度した約束を破るべきではない。
Furigana: いちどしたやくそくをやぶるべきではない。
Romaji: Ichido shita yakusoku o yaburu beki de wa nai.
English: One shouldn’t break a promise once it’s made.
Example #9
歩きながらスマホを見るべきではない。
Furigana: あるきながらスマホをみるべきではない。
Romaji: Arukinagara sumaho o miru beki de wa nai.
English: You shouldn’t look at your smartphone while walking.
Example #10
言語を学ぶ時、間違いを恐れるべきではない。
Furigana: げんごをまなぶとき、まちがいをおそれるべきではない。
Romaji: Gengo o manabu toki, machigai o osoreru beki de wa nai.
English: We shouldn’t be afraid of making mistakes when learning a language.
Notes & Nuances
📌 Important Points
Moral Obligation vs. Personal Command
It expresses a general ‘right or wrong’ rather than a personal command like ‘don’t go’.
Example: 彼は行くべきではない。 (He should not go.)
Expressing Regret
When used in the past tense (beki de wa nakatta), it expresses strong regret.
Example: あんな高い靴を買うべきではなかった。 (I shouldn’t have bought such expensive shoes.)
⚠️ Common Mistakes
❌ してべきではない (Shite beki de wa nai)
✅ すべきではない (Subeki de wa nai) or するべきではない (Suru beki de wa nai).
For ‘suru’ verbs, ‘subeki’ is the traditional/more formal form, but ‘surubeki’ is also widely accepted.
❌ Using ‘beki de wa nai’ for light, personal advice.
✅ ～ないほうがいい (Nai hou ga ii).
‘Beki de wa nai’ sounds like a moral lecture. If you just want to give friendly advice, use ‘nai hou ga ii’.
🏛️ Cultural Context
Politeness Level: It is a direct expression of judgment, so it should be used carefully with superiors unless you are stating a general rule.
Social Situations: Commonly used by parents to children, teachers to students, or in social commentary.
Regional Variations: Standard Japanese. In some dialects, ‘beki’ might be replaced by local obligation markers.
🔍 Subtle Differences
～てはいけない (Te wa ikenai) vs. べきではない (Beki de wa nai)
‘Te wa ikenai’ is a strict prohibition (rules/laws), whereas ‘beki de wa nai’ is based on logic, common sense, or morality.
When to use: Use ‘beki de wa nai’ when the reason is ‘it’s not the right thing to do’.
～ないほうがいい (Nai hou ga ii) vs. べきではない (Beki de wa nai)
‘Nai hou ga ii’ is a suggestion (You’d better not). ‘Beki de wa nai’ is a strong moral statement.
When to use: Use ‘nai hou ga ii’ for soft suggestions.
📝 Conjugation Notes
– Verb (Dictionary Form) + べきではない – Suru (do) -> すべきではない / するべきではない – Past Tense: べきではなかった (Should not have done…)
🔊 Pronunciation Tips
Ensure the ‘de wa’ is pronounced clearly. In casual speech, ‘de wa’ often contracts to ‘ja’ (べきじゃない).
🧠 Memory Tips
Think of ‘beki’ as ‘duty’ or ‘right way’. ‘Beki de wa nai’ means ‘it is not the right way’ or ‘it is not your duty’.
Other Grammar
I’m a software engineer based in Japan, with experience in developing web and mobile applications. I’m passionate about technology, especially in DevOps, AI, and app development using platforms like AWS, Flutter, and Node.js. My goal is to build a website that shares knowledge about the Japanese language and IT, helping everyone learn and grow more easily in the digital era.