imperceptible
gb/ˌɪmpɚsˈɛptɪbəl/ us/ˌɪmpɚsˈɛptɪbəl/
C1
English
Senses
0 senses
adjective
formal
C1
property
1
too slight to notice
So small or subtle that people cannot notice it.
Usage pattern:
imperceptible (to [someone])
Common mistake:
Learners sometimes limit it to vision only; it can refer to any sense or to detection (e.g., changes, differences, sounds).
Synonyms
unnoticeable (Direct and common; emphasizes that people don’t notice it.)
|
undetectable (Stronger; suggests even careful checking or instruments may not find it.)
|
barely perceptible (Similar meaning; suggests it can be noticed, but only just.)
Antonyms
noticeable (Easy to observe or pick up.)
|
obvious (Very clear and hard to miss.)
|
perceptible (Able to be noticed or detected.)
Collocations
imperceptible change
|imperceptible difference
|imperceptible shift
|imperceptible movement
|imperceptible pause
|imperceptible smile
|imperceptible tremor
|imperceptible rise
|imperceptible variation
|imperceptible improvement
Themes
perception
|description
Examples
- There was an imperceptible hesitation before she answered.
- The lighting changed in an imperceptible way as the scene shifted.
- At first the pain relief was imperceptible, but it grew over time.
Learner examples
- The difference is imperceptible.
- His smile was almost imperceptible.
adjective
formal
C1
property
2
happening too gradually to notice
Changing so slowly that people do not notice it.
Usage pattern:
imperceptible [change/increase/decline]
Common mistake:
Learners sometimes use it for any slow change; it usually means the change is not noticed as it happens.
Synonyms
gradual (Simply means slow; does not necessarily imply ‘not noticeable’.)
|
incremental (Step-by-step change; can be measurable even if small.)
|
subtle (Hard to notice; not necessarily related to speed.)
Antonyms
sudden (Happening quickly, often unexpectedly.)
|
abrupt (Sharp, clearly noticeable change.)
Collocations
imperceptible increase
|imperceptible decline
|imperceptible growth
|imperceptible progression
|imperceptible improvement
|imperceptible deterioration
|imperceptible rise
|imperceptible shift
|imperceptible transition
|imperceptible fading
Themes
time
|change
Examples
- The days became longer by an imperceptible amount each week.
- Her confidence grew in imperceptible steps during the course.
- The company’s influence expanded through imperceptible changes in policy.
Learner examples
- The change was imperceptible at first.
Grammar
Dictionary form
imperceptible
IPA
GB/ˌɪmpɚsˈɛptɪbəl/
US/ˌɪmpɚsˈɛptɪbəl/
Syllables & stress
im - per - cept - ible (4 syllables)
Stress on 2nd syllable (per)
Word forms
Adjective
- Base: imperceptible
Word family
Core family
Related words
perceptive
adjective C1
perceptibly
adverb
Negative and opposite forms
imperceptibly
adverb C1
unperceptive
adjective
Advanced or less common
perceptual
adjective
misperceive
verb
misperception
noun
Expressions
almost imperceptible
1/ˈɔlmˌoʊst ˌɪmpɚsˈɛptɪbəl/
fixed phrase
barely noticeable
Very, very hard to notice.
Examples
- He gave an almost imperceptible nod to signal agreement.
- There was an almost imperceptible change in her tone.
- The boat drifted forward with an almost imperceptible movement.
imperceptible to the naked eye
1/ˌɪmpɚsˈɛptɪbəl tə ðə nˈeɪkɪd ˈaɪ/
fixed phrase
formal
not visible without equipment
Not possible to see without special tools.
Examples
- The crack was imperceptible to the naked eye but showed up in the scan.
- These organisms are imperceptible to the naked eye and require a microscope.
- The color shift is imperceptible to the naked eye unless you compare the samples side by side.