opacity
gb/oʊpˈæsəti/ us/oʊpˈæsəti/
C1
English
Senses
0 senses
Noun
C1
property
1
lack of transparency to light
Opacity is how much something blocks light.
Usage pattern:
the opacity of [material/object]
Common mistake:
Learners sometimes confuse opacity (blocks light) with transparency (lets light through).
Synonyms
opaqueness (More direct and less formal; same meaning.)
|
cloudiness (Often suggests a liquid that is not clear, not any solid object.)
Antonyms
transparency (The quality of letting light pass through clearly.)
|
clarity (Often used for liquids or images being easy to see through.)
Collocations
high opacity
|low opacity
|the opacity of glass
|the opacity of water
|reduce opacity
|increase opacity
|light opacity
|optical opacity
|surface opacity
|measure opacity
Themes
materials
|science
|daily_life
Examples
- Frosted glass gets its opacity from the textured surface.
- The lab measured the water’s opacity after the storm.
- As the paint dried, its opacity increased and the wall color stopped showing through.
Learner examples
- This glass has high opacity.
- The water has low opacity today.
Noun
technical
C1
quantity
2
degree of being opaque
Opacity can also mean a level, like a number or percent.
Usage pattern:
an opacity of [number/percentage]
Common mistake:
Don’t use *an opacity* to mean simply ‘something is opaque’ unless you are talking about a measurable level.
Synonyms
density (In everyday talk it can overlap, but density is not the same physical measure.)
Antonyms
transparency (Can also be measured as a level in similar contexts.)
Collocations
opacity value
|opacity level
|opacity reading
|opacity measurement
|set the opacity
|adjust the opacity
|opacity percentage
|opacity scale
|opacity threshold
|peak opacity
Themes
science
|measurement
|materials
Examples
- The display lets you set an opacity of 70%.
- The sensor reports opacity readings every minute.
- At higher opacity values, the background becomes harder to see.
Learner examples
- Set the opacity to 50%.
- This layer has 80% opacity.
Noun
formal
C1
abstract
3
lack of clarity or openness
Opacity can mean that something is hard to understand because it is not clear or open.
Usage pattern:
the opacity of [process/system/statement]
Common mistake:
Learners may overuse opacity when ‘unclear’ or ‘confusing’ would be more natural in casual speech.
Synonyms
obscurity (Emphasizes being hard to understand, sometimes due to complexity.)
|
lack of transparency (Focuses on not being open or accountable.)
|
murkiness (More informal; suggests confusion or suspicion.)
Antonyms
transparency (Openness and clarity about what is happening.)
|
clarity (Ease of understanding and seeing what is meant.)
Collocations
bureaucratic opacity
|corporate opacity
|government opacity
|opacity of the process
|opacity of the rules
|opacity in decision-making
|regulatory opacity
|legal opacity
|financial opacity
|deliberate opacity
Themes
communication
|business
|government
Examples
- Employees complained about the opacity of the promotion process.
- The report criticized the opacity of the company’s finances.
- The policy’s opacity made it hard for customers to know what they were agreeing to.
Learner examples
- The rules have too much opacity.
- We want more transparency and less opacity.
Noun
technical
C2
entity
4
whiteness in medical imaging
In medicine, an opacity is a whiter area on a scan.
Usage pattern:
an opacity in [body part/scan]
Synonyms
shadow (Common non-technical term used by patients; less precise.)
Antonyms
clear area (Not a standard technical antonym, but the opposite finding on imaging.)
Collocations
pulmonary opacity
|lung opacity
|focal opacity
|diffuse opacity
|ground-glass opacity
|an opacity on the X-ray
|an opacity in the left lung
|new opacity
|resolving opacity
|persistent opacity
Themes
health
|medicine
Examples
- The radiologist noted a small opacity in the right upper lobe.
- Follow-up imaging showed that the opacity had resolved.
- A new opacity on the chest X-ray prompted further tests.
Grammar
Dictionary form
opacity
IPA
GB/oʊpˈæsəti/
US/oʊpˈæsəti/
Syllables & stress
opa - city (2 syllables)
Stress on 2nd syllable (city)
Word forms
Noun
- Base: opacity
- Plural: opacities, opacity
Word family
Forms
opacities
noun
Core family
opaque
adjective B2
Related words
opaquely
adverb
opaqueness
noun
Negative and opposite forms
transparent
adjective B2
transparency
noun C1
Advanced or less common
opacify
verb
opacification
noun
Expressions
ground-glass opacity
1/ɡɹˈaʊnd ɡlˈæs oʊpˈæsəti/
fixed phrase
technical
hazy area on lung scan
A ground-glass opacity is a hazy area on a lung scan.
Examples
- The CT report mentioned ground-glass opacity in both lungs.
- Ground-glass opacity can have several possible causes.
- Repeat imaging showed less ground-glass opacity than before.
opacity level
1/oʊpˈæsəti lˈɛvəl/
fixed phrase
technical
amount of opacity
An opacity level is a chosen amount of opacity.
Examples
- Lower the opacity level so the text behind it is visible.
- The default opacity level is 100%.
- Try a 30% opacity level for a subtle watermark.
opacity setting
1/oʊpˈæsəti sˈɛtɪŋ/
fixed phrase
technical
control for opacity in software
The opacity setting is where you change transparency.
Examples
- Change the opacity setting for the top layer.
- If the highlight is too strong, reduce the opacity setting.
- The app remembers your last opacity setting.
opacity slider
1/oʊpˈæsəti slˈaɪdɚ/
fixed phrase
technical
UI slider for transparency
An opacity slider is a bar you drag to change opacity.
Examples
- Drag the opacity slider to the left to make it more transparent.
- The opacity slider is in the Layers panel.
- I can’t find the opacity slider on mobile.