Structure
Verb[て]+ は + いけない
Details
Part of Speech
Verb
Word Type
Auxiliary Verb
Register
Formal
About てはいけない
てはいけない is used in Japanese to express that (A) 'cannot', or 'must not' be done. It is the combination of a verb in て form, the は particle, and the negative potential form of 行く (to be able to go). In this way, it literally means '(A) cannot/is not able to go'.
Although は can be dropped from many phrases and expressions, the は in this particular grammar point is usually not. This is because いけない would then become the second action in a sequence of events (the usual function of て form). However, to make this more casual, ては is often changed to ちゃ (ては becomes ちゃ), or じゃ (では becomes じゃ), as this is easier to say.
Caution
Apart from いけない; ならない and だめ are also frequently used to get across the same meaning. However, they are used in different situations.
いけない - Fairly neutral. Used in both spoken and written language.
ならない - Fairly formal. Used mostly in written language.
だめ - Very casual. Used almost exclusively in spoken language.
Antonyms
Related
Examples
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そこに入ってはいけない。
You must not go in there.
クジラを食べてはいけない。
We must not eat whale.
このビルに入ってはいけない。
You must not go into this building.
晩ごはんの前に、お菓子を食べてはいけない。
You must not eat candy before dinner.
この池で泳いではいけません。
You must not swim in this pond.
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"HAVE TO", "NEED TO" "SHOULD HAVE", "I WISH...HADN'T" in Japanese
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[DBJG] A Dictionary of Basic Japanese Grammar
Page 528
Genki I
Page 120
Genki I 2nd Edition
Page 152
Marugoto Elementary 2 (A2) Rikai
Page 48
Tae Kim's Japanese Grammar Guide
Page 140
みんなの日本語 I
Page 98 [CH 15]
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てはいけない – Grammar Discussion
Most Recent Replies (21 in total)
Jake
must not・may not
Structure
- Verb[て] + は・いけない
meaning
must not・may notView on Bunpro
Lilalas
This is another grammar point where you should probably also mention the 漢字 spelling:
ては行けない
mrnoone
Generally, when the verb is used as auxiliary etc, it is written using kana alone. That way it is distinguished from using it as a standalone verb.
That’s why てはいけない、ておく(て置く)、てみる(て見る) are all written in kana. Using kanji may confuse readers.
CrisH
This says to use long form て, but in 車で いってはいけない, いって is the shortest て form the verb has, isn’t it? Am I missing something? I thought the long form was 行かなくて, as when you’re saying you must do something.
Thanks,
CrisPushindawood
@CrisH Hey! I think that the confusion may have come from the wording of the hint, with “て + いく” immediately following “long form.” The long form refers to the whole combination of て + は + いけない as opposed to shortened phrases like いっちゃだめ, or いったアカン (Kansai dialect). Cheers!
CrisH
Ah, that’s probably it. I haven’t come across that yet, so I assumed long form was 行かなくて and short form was 行って. Thanks for clarifying
Pushindawood
@CrisH 行かなくて and 行かないで are the negative て-forms of the verb 行く, while 行って is the plain て-form. 行かなくてはいけない means “(you) must go,” while 行ってはいけない means “(you) must not go.” Cheers!
deltacat3
Does anyone know why は is used in this construction and how it interacts with a verbs て-form? I am just curious is all.
testing
What’s up with the sudden “いけません” in the “この池で泳いではいけません 。” example? It’s not mentioned in the Meaning section.
mrnoone
Hey and long time no see
てはいけません is a polite form of てはいけない. It is made just like the ordinary polite negative form of a verb.
で comes from the fact that the てform of 泳ぐ is 泳いで (it is still called a て form even though technically for those verbs its で).So:
泳いで - て form of verb 泳ぐ
泳いでいけない - short form
泳いでいけません - polite formI hope it helps,
Cheers
Ask if you have any questions, I have caught a small cold so I might not explain clearly
Chewt
If anyone was wondering where in [DBJG] this grammar is, its on page 528.
lasyat
Why does the hint say て+いくinstead of て+いける? This confused me a bit.
Pushindawood
@lasyat Hey! The hints are just there to steer you clear of using something like てはならない. If we provide too much of the actual grammar point (the partial conjugation in this case) then it becomes too easy to answer. The hint is just meant to get you in the right mindset (okay, this question is asking me to conjugate to the long form of て (as opposed to なくちゃ or なきゃ) first and then not use ならない). Cheers!
hachimagu
Hi,
I would suggest to include “は + いけません” in the meaning box as well.
Kai
Not that it really matters, but it looks like there’s a rogue space in the title of this topic
mrnoone
@Kai @hachimagu
Included
GrimeyPlopFlop
If this conjugation uses the verb 行く, why does the polite negative and non-polite negative conjugate as いけない and いけません instead of いかない and いきません like 行く does normally?
ResFort
This construction uses the potential form of 行く (行ける, “can go”), not the dictionary form.
So when conjugating it into the negative we get いけない/いけません (行ける itself is an ichidan verb).The literal translation for Aてはいけない is then something like “doing A cannot go”, which is better interpreted as “must not do A”.
GrimeyPlopFlop
Ah, that makes a a lot of sense, thank you!
notasas
The bunpro description states this contains “negative potential form of 行く”, however I’ve just encountered this:
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