ill defined

USAGE SUMMARY

The phrase "ill defined" is correct and usable in written English, although it is more commonly written as "ill-defined" with a hyphen.
You can use it to describe something that is not clearly or precisely defined, often in academic or technical contexts. Example: "The concept of happiness is often considered ill-defined, making it difficult to measure in psychological studies."

✓ Grammatically correct

News & Media

Science

Human-verified examples from authoritative sources

Exact Expressions

11 human-written examples

As a health threat, it was ill defined.

The New York Times - Science

And their long-term risks are ill defined.

The New York Times

It is ill defined at best, hypocritical at worst.

The New York Times - Sports

Once again, the figure is very crude and ill defined.

Independent

The instruments' place in museums too is ill defined.

The New York Times

"That's because they were so ill defined," he said.

The New York Times - Sports

Human-verified similar examples from authoritative sources

Similar Expressions

49 human-written examples

"It's easiest to define somebody when they're ill-defined, and John Kerry's ill-defined".

The New York Times

It is an intentionally ill-defined term.

The New Yorker

"This process is open-ended and ill-defined".

The New York Times

("Theft" was another ill-defined term in the speech).

The New Yorker

They'd have some ill-defined "compensation" for missing work.

The New Yorker

Expert writing Tips

Best practice

Ensure the context provides enough information for the reader to understand what specific aspect is "ill defined". A vague statement can leave the reader confused.

Common error

Avoid using "ill defined" when you mean something was poorly executed or implemented. "Ill defined" refers specifically to a lack of clarity in definition, not a failure in practice.

Linguistic Context

The phrase "ill defined" functions primarily as a descriptive adjective phrase. It modifies a noun to indicate that the noun lacks a clear or precise definition. Ludwig AI confirms its usability in written English, although the hyphenated form, "ill-defined", is more common.

Expression frequency: Common

Frequent in

Science

42%

News & Media

42%

Wiki

16%

Less common in

Formal & Business

0%

Encyclopedias

0%

Social Media

0%

Ludwig's WRAP-UP

In summary, the phrase "ill defined" is a grammatically sound and frequently used expression to denote a lack of clarity or precision in a definition. Ludwig AI indicates that while correct, the hyphenated form "ill-defined" is often preferred. It is commonly found in news, media, and scientific contexts. When using "ill defined", consider whether the hyphenated form enhances readability, and ensure the context clearly indicates what aspect lacks definition. Alternative phrases like "poorly defined" or "vaguely defined" can offer nuanced substitutes. Avoid using "ill defined" when you mean "poorly executed".

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

poorly defined

Implies a definition that is inadequate or lacking in detail.

vaguely defined

Suggests a definition that is indistinct or imprecise.

ambiguously defined

Highlights uncertainty and multiple possible interpretations in the definition.

imprecisely defined

Emphasizes the lack of exactness or accuracy in the definition.

inadequately defined

Focuses on the insufficiency or incompleteness of the definition.

loosely defined

Suggests a flexible or broad interpretation of the definition.

unclearly defined

Indicates a lack of clarity or transparency in the definition.

indistinctly defined

Highlights the lack of sharp boundaries or clear features in the definition.

fuzzily defined

Emphasizes the lack of sharpness and precision in the definition.

sketchily defined

Suggests a definition that is only outlined briefly and lacks detail.

FAQs

How can I use "ill defined" in a sentence?

You can use "ill defined" to describe concepts, boundaries, roles, or terms that lack clear definition. For example, "The long-term risks of this treatment are "ill defined"."

What's a synonym for "ill defined"?

Synonyms for "ill defined" include "poorly defined", "vaguely defined", or "ambiguously defined". Choose the synonym that best fits the specific nuance you want to convey.

Is it better to write "ill defined" or "ill-defined"?

While both forms are acceptable, "ill-defined" (with a hyphen) is often preferred, especially in formal writing, as it improves readability by clearly indicating that "ill" modifies "defined".

What is the difference between "ill defined" and "undefined"?

"Ill defined" suggests a definition exists but is unclear or imprecise. "Undefined" implies there is no definition at all. For example, a role might be "ill defined" if its responsibilities are vague, but it's "undefined" if it simply doesn't exist.