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Synonyms

imperceptible

American  
[im-per-sep-tuh-buhl] / ˌɪm pərˈsɛp tə bəl /

adjective

  1. very slight, gradual, or subtle.

    the imperceptible slope of the road.

  2. not perceptible; not perceived by or affecting the senses.

    Synonyms:
    undetectable, unperceivable, hidden

noun

  1. something not capable of being perceived by the senses.

    metaphysical speculation about imperceptibles.

imperceptible British  
/ ˌɪmpəˈsɛptɪbəl /

adjective

  1. too slight, subtle, gradual, etc, to be perceived

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of imperceptible

From the Medieval Latin word imperceptibilis, dating back to 1520–30. See im- 2, perceptible

Explanation

If it's imperceptible, it's impossible to perceive with any of the senses. The world might be spinning, but it's imperceptible from your couch. Within the word imperceptible you see the word percept, which means "the object of your perception." Like impossible, the im in imperceptible means it cannot be perceived. Imperceptible is rarely used in the absolute sense of the word — it is usually paired with almost. Horton hears the Who but the tiny sounds of the Whos were almost imperceptible to everyone else.

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Vocabulary lists containing imperceptible

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Methane gas may be imperceptible, but the garbage that produces it is not -- Tiltil's 17,000 inhabitants have grown increasingly concerned about the health impact of such drastic pollution.

From Barron's • May 13, 2026

But the opposite, reflective face bears an image incised in finely engraved lines that under normal conditions is virtually imperceptible to the naked eye.

From The Wall Street Journal • Nov. 12, 2025

"Traditionally, the intense heat of firing destroys any biological residue. However, our technique has been able to reveal fingerprint ridges that would otherwise remain imperceptible."

From Science Daily • Nov. 2, 2025

The hum of the electric motor is imperceptible, and it is only at speed that the sound of the rolling wheels on the road breaks through.

From BBC • Sep. 3, 2025

It is tempting to think of this as some kind of giant continent-sized car crash, but of course it happened with imperceptible slowness.

From "A Walk in the Woods" by Bill Bryson

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