must not

USAGE SUMMARY

The phrase "must not" is correct and usable in written English.
It is typically used to indicate prohibition or something that is not allowed. Example: "You must not enter the restricted area without permission."

✓ Grammatically correct

News & Media

Formal & Business

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

It must not.

The Economist

It must not continue.

Independent

This must not happen".

The New York Times

You must not negotiate.

The New York Times

"Shops must not close.

The New York Times

It must not emit.

The New Yorker

We must not.

The Guardian

We must not stop".

Independent

One must not romanticize.

The New York Times

We must not flinch.

Independent

We must not overcompensate".

The New York Times

Expert writing Tips

Best practice

Use "must not" to clearly and unequivocally express prohibition or when stating a rule or regulation that should not be broken. For instance, in safety instructions or legal documents, it provides a strong and direct command.

Common error

Avoid using "must not" in casual conversation where a softer suggestion like "shouldn't" or "don't" would be more appropriate. Overusing it can make your speech sound overly formal or aggressive.

Linguistic Context

The phrase "must not" functions as a prohibitive auxiliary verb phrase. It combines the modal verb 'must' with 'not' to express a strong negative obligation or prohibition. Ludwig AI confirms its use to indicate something is forbidden.

Expression frequency: Very common

Frequent in

News & Media

65%

Formal & Business

20%

Science

5%

Less common in

Encyclopedias

0%

Wiki

0%

Reference

0%

Ludwig's WRAP-UP

In summary, "must not" is a prohibitive phrase used to express a strong negative obligation or prohibition. Ludwig AI identifies it as grammatically correct and commonly used, primarily in news and formal business contexts. While effective for conveying rules and regulations, overuse in informal settings should be avoided. Alternatives like "is forbidden" or "cannot" can be used depending on the desired level of formality.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

is forbidden

Replaces "must not" with a passive construction expressing prohibition.

is not allowed

Uses a more direct and explicit expression of prohibition.

is prohibited

A formal and legalistic synonym for "must not".

cannot

A more concise and common alternative to indicate impossibility or prohibition.

may not

Indicates that something is not permitted, often used in formal contexts.

should not

Expresses a strong recommendation against something, but less forceful than "must not".

ought not to

A more formal and somewhat archaic equivalent of "should not".

is inadvisable

Indicates that something is not a good idea.

it is essential to avoid

Emphasizes the importance of preventing something from happening.

it is imperative to refrain from

A highly formal way of saying that something should be avoided.

FAQs

How to use "must not" in a sentence?

Use "must not" to indicate a prohibition or something that is not allowed. For example, "You "must not" enter without permission" or "Employees "must not" disclose confidential information".

What can I say instead of "must not"?

You can use alternatives like "is forbidden", "is not allowed", or "cannot" depending on the context. "is forbidden" is more formal, while "cannot" is more common in everyday speech.

What's the difference between "must not" and "should not"?

"Must not" indicates a strict prohibition, while "should not" expresses a strong recommendation against something. "You "must not" cheat" implies a rule that cannot be broken, whereas "You "should not" eat too much sugar" is a suggestion for better health.

Which is correct, "must not" or "don't have to"?

"Must not" means something is prohibited, while "don't have to" means something is not required. "You "must not" drive without a license" forbids driving without a license, but "You "don't have to" come if you're busy" indicates attendance is optional.