[uhn-fath-uh-muh-buh l]


not able to be fathomed, or completely understood; incomprehensible: heroism in the face of unfathomable conflict.
not able to be measured with a sounding line, or fathomed: unfathomable depths of the ocean.

Related formsun·fath·om·a·ble·ness, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for unfathomable

Contemporary Examples of unfathomable

Historical Examples of unfathomable

  • And with her straight, unfathomable glance she answered that she would be so, of course.

    The Secret Agent

    Joseph Conrad

  • His eyes were dark, and they held an unfathomable melancholy.

    Tiverton Tales

    Alice Brown

  • As she turned to go her eyes thanked him with an unfathomable glance.

    The Black Bag

    Louis Joseph Vance

  • Is it pale and gray with heat, full of sunshine, and unfathomable in depth?

  • They had leant, so to say, one on the other above an unfathomable depth, attracted to it by its horror.

    Therese Raquin

    Emile Zola

British Dictionary definitions for unfathomable



incapable of being fathomed; immeasurable
Derived Formsunfathomableness, noununfathomably, 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 unfathomable

1610s, originally in the figurative sense, of feelings, conditions, etc., from un- (1) "not" + fathomable. Literal sense attested from 1670s. Related: Unfathomably.

Online Etymology Dictionary, © 2010 Douglas Harper