Used and loved by millions
Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.

Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com
rarefy
Grammar usage guide and real-world examplesUSAGE SUMMARY
The word "rarefy" is correct and usable in written English.
You can use the word when referring to a process in which something is made less dense or more subtle. For example, you could say "The air was rarefied by the blast of wind."
✓ Grammatically correct
News & Media
Science
Encyclopedias
Alternative expressions(7)
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Human-verified examples from authoritative sources
Exact Expressions
7 human-written examples
The star in question, however, when some billions of years had passed since its birth, and its companions began to rarefy, was not satisfied with its destiny and became restless — to such a point that its restlessness became visible even to those of us who are "very" distant and circumscribed by a "very" brief life.
News & Media
Of course it's serious, and art is serious, but I'm not going to rarefy it".
News & Media
In other words, there is more than enough chutzpah and get-off-your-assing to go around; plenty of will, desire and effort to find some way of defending and practising intellectually robust humanities education in a political environment that seems to be able, almost effortlessly, to suffocate, rarefy or commodify it.
News & Media
Almost everyone fails on them: supersede, naphtha, tranquillity, liquefy, sacrilegious, kimono, paraffin, rarefy, picnicking, battalion.
News & Media
The primary activity of warmth is to move fast and to dilate and rarefy matter, whereas that of cold is to hinder movement and to condense matter.
Science
He explains that the heavenly bodies can only move with a circular movement because the luminosity in them is incapable of rarefaction or condensation, and as a result cannot incline the parts of their matter upward (to rarefy them) or downward (so as to condense them).
Science
Because the elements, on the other hand, can be rarefied and condensed, they can incline the luminosity in themselves away from the center of the universe, so as to rarefy it, or toward the center so as to condense it, and this accounts for their natural capacity to move up and down.
Science
Human-verified similar examples from authoritative sources
Similar Expressions
3 human-written examples
Sound moving through air also compresses and rarefies the gas in the direction of travel of the sound wave as they vibrate back and forth.
Encyclopedias
A surer bet is the bianca tradizionale, where a glaze of pork lard rarefies simple mozzarella.
News & Media
By going back to the thing itself, phenomenology aimed at eluding the errors of both empiricism (reducing reality to the measurable) and idealism (rarefying reality into abstraction and subjectivism).
Science
Expert writing Tips
Best practice
Use "rarefy" when you want to describe making something less dense, either literally (like air) or figuratively (like an idea or concept). For instance, "the artist sought to rarefy the heavy atmosphere of the room with delicate lighting".
Common error
While "rarefy" is a valid word, it can sound overly formal or pretentious in everyday conversation. Opt for simpler alternatives like "thin out" or "lighten" in informal settings to avoid sounding unnatural.
Source & Trust
87%
Authority and reliability
4.2/5
Expert rating
Real-world application tested
Linguistic Context
The verb "rarefy" primarily functions to describe the action of making something less dense or thinner. As Ludwig highlights, this can apply to both physical substances, like air, and abstract concepts, like ideas, making them more subtle or refined. Examples show its use in scientific and artistic contexts.
Frequent in
Science
30%
News & Media
40%
Encyclopedias
30%
Less common in
Formal & Business
0%
Wiki
0%
Reference
0%
Ludwig's WRAP-UP
In summary, "rarefy" is a verb that means to make something less dense or thinner, applicable both literally and figuratively. As Ludwig points out, it's grammatically correct but may sound overly formal in casual contexts. Usage is relatively uncommon, and it most frequently appears in scientific, news, and encyclopedic sources. When using "rarefy", consider if simpler alternatives like "thin out" or "lighten" might be more appropriate for your audience. Ludwig's examples demonstrate its effective use in describing both physical and abstract processes.
More alternative expressions(6)
Phrases that express similar concepts, ordered by semantic similarity:
make less dense
Focuses on the reduction of density, a primary meaning of "rarefy".
thin out
Implies a reduction in thickness or concentration, similar to making something less dense.
make more subtle
Highlights the aspect of making something finer or more ethereal, a metaphorical extension of "rarefy".
attenuate
Suggests a weakening or thinning, often used in scientific contexts.
sublimate
Implies a transformation to a more refined or spiritual form, sharing a sense of elevation with "rarefy".
expand
Focuses on increasing the volume or size while potentially decreasing density.
dilate
Suggests widening or expanding, often used in a physical or biological context.
make porous
Emphasizes the creation of spaces or holes, related to reducing the overall density of a material.
decompress
Focuses on reducing pressure or density, often in the context of gases or confined spaces.
lighten
Indicates making something less heavy or dense, applicable in both physical and metaphorical senses.
FAQs
How can I use "rarefy" in a sentence?
What can I say instead of "rarefy"?
Alternatives to "rarefy" include "thin out", "make less dense", "attenuate", or "sublimate", depending on the specific context.
Is it correct to use "rarefy" when describing abstract concepts?
Yes, "rarefy" can be used metaphorically to describe making abstract concepts more subtle or refined. For example, you might say a writer attempted to "rarefy" a complex idea into a more accessible form.
What is the difference between "rarefy" and "condense"?
"Rarefy" means to make something less dense or thinner, while "condense" means to make something denser or more compact. They are antonyms, representing opposite processes.
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Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Source & Trust
87%
Authority and reliability
4.2/5
Expert rating
Real-world application tested