red line

USAGE SUMMARY

'red line' is correct and usable in written English.
It means a limit that should not be crossed or a set of principles that should not be violated. For example, "The government drew a red line that international aid would not go beyond a certain level."

✓ Grammatically correct

News & Media

Science

Politics

Human-verified examples from authoritative sources

Exact Expressions

57 human-written examples

That's a red line".

The Guardian

I like the red line.

The New York Times

"The red line is now".

The New York Times

"This is the red line".

The New York Times

This is a red line".

Independent

That's a red line for us".

The New York Times

We're committed to that red line".

The New York Times

That's what the red line shows.

Independent

Human-verified similar examples from authoritative sources

Similar Expressions

3 human-written examples

"Yemen is Saudi Arabia's proverbial 'red line.'".

Huffington Post

Union Station, Red Line.

The New York Times - Travel

The Red Line was skipping downtown stations.

The New Yorker

Expert writing Tips

Best practice

In technical or scientific writing, ensure the "red line" is visually identified in accompanying figures or graphs to avoid ambiguity.

Common error

Writers often confuse the act of setting a limit with the act of violating it. You "draw" or "set" a "red line" to establish a boundary, but you "cross" a "red line" when that boundary is breached. Mixing these up can lead to logical inconsistencies in your narrative.

Linguistic Context

The phrase "red line" acts as a compound noun or noun phrase. In most of the instances provided by Ludwig, it serves as the direct object of a sentence (e.g., "I drew a red line") or a subject defining a standard (e.g., "The red line is now").

Expression frequency: Very common

Frequent in

News & Media

55%

Science

30%

Politics

10%

Less common in

Wiki & General

3%

Sports

1%

Social Media

1%

Ludwig's WRAP-UP

The phrase "red line" is a versatile and powerful tool in English writing. According to Ludwig AI, it is consistently used across elite journalistic and scientific sources to define absolute thresholds. Whether you are describing a data point in a technical paper or a non-negotiable policy in a diplomatic essay, "red line" carries an inherent sense of weight and importance. It is most effective when the consequences of crossing the line are clearly understood by the reader. Its high frequency in news media suggests it is a staple of contemporary rhetoric for describing conflicts and limits. Ultimately, using "red line" adds a layer of clarity and seriousness to your writing, provided it is not overused in trivial contexts.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

non-negotiable

Focuses on the refusal to compromise rather than the boundary itself

boundary

A more general term for a limit, often used in social or physical contexts

threshold

Describes the magnitude or intensity that must be exceeded for a result to occur

hard limit

Emphasizes that the restriction is absolute and inflexible

breaking point

Refers to the moment a system or person fails after a limit is reached

demarcation line

Technical term for a physical or conceptual border between groups

ultimatum

A final demand which, if rejected, leads to a breakdown in relations

breaking point

Focuses on the stress limit of a particular situation or object

point of no return

Refers to a stage where one must continue on a course of action

rubicon

A metaphorical line that, once crossed, allows for no turning back

FAQs

What is the meaning of a "red line" in politics?

In politics, a "red line" represents a metaphorical boundary or limit which, if crossed by an opposing party, will trigger a specific and often severe response.

How do I use "red line" in a sentence?

You can use it literally, as in "The <a href="/s/red+line" target="_blank" rel="alternative">red line on the graph shows a sharp increase in temperature", or metaphorically: "Respecting human rights is a <a href="/s/red+line" target="_blank" rel="alternative">red line for our organization".

What can I say instead of "red line"?

Depending on your context, you might use "<a href="/s/non-negotiable" target="_blank" rel="alternative">non-negotiable", "<a href="/s/ultimate+limit" target="_blank" rel="alternative">ultimate limit", or "<a href="/s/breaking+point" target="_blank" rel="alternative">breaking point".

Is "red line" considered formal English?

Yes, it is widely accepted in professional and academic settings, particularly within political science, international relations, and technical data analysis.