very slight, gradual, or subtle: the imperceptible slope of the road.
not perceptible; not perceived by or affecting the senses.


something not capable of being perceived by the senses: metaphysical speculation about imperceptibles.

Origin of imperceptible

From the Medieval Latin word imperceptibilis, dating back to 1520–30. See im-2, perceptible
Related formsim·per·cep·ti·bil·i·ty, im·per·cep·ti·ble·ness, nounim·per·cep·ti·bly, adverb

Synonyms for imperceptible Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for imperceptibly

Contemporary Examples of imperceptibly

  • The sun, I notice on this day when Daylight Saving has reverted to Standard Time, has imperceptibly set.

    The Daily Beast logo
    Barack and the Boss

    Charles Michener

    November 3, 2008

Historical Examples of imperceptibly

  • Steadily, imperceptibly, and surely, until it was paramount and supreme.

  • I had seen it, the slight puff of the earlobes—oh, so imperceptibly slight.

  • Imperceptibly, Helen straightened herself and took a breath.

    Moor Fires

    E. H. (Emily Hilda) Young

  • Slowly, imperceptibly, the orientation of the planet has changed.

    The Life Radiant

    Lilian Whiting

  • He drifted away from Miriam imperceptibly, without knowing he was going.

    Sons and Lovers

    David Herbert Lawrence

British Dictionary definitions for imperceptibly



too slight, subtle, gradual, etc, to be perceived
Derived Formsimperceptibility or imperceptibleness, nounimperceptibly, adverb
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

Word Origin and History for imperceptibly



early 15c., from French imperceptible (early 15c.), from Medieval Latin imperceptibilis, from assimilated form of in- "not, opposite of" (see in- (1)) + perceptibilis (see perceptible). Related: Imperceptibly. OED marks imperceivable as "Now rare."

Online Etymology Dictionary, © 2010 Douglas Harper