View synonyms for unfathomable


[ uhn-fath-uh-muh-buhl ]


  1. not able to be fathomed, or completely understood; incomprehensible:

    heroism in the face of unfathomable conflict.

  2. not able to be measured with a sounding line, or fathomed:

    unfathomable depths of the ocean.


/ ʌnˈfæðəməbəl /


  1. incapable of being fathomed; immeasurable
  2. incomprehensible

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Derived Forms

  • unˈfathomableness, noun
  • unˈfathomably, adverb

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Other Words From

  • un·fathom·a·ble·ness noun

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Word History and Origins

Origin of unfathomable1

First recorded in 1610–20; un- 1( def ) + fathom ( def ) + -able ( def )

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Example Sentences

At every moment, subatomic particles stream in unfathomable numbers through your body.

Her words remind us that Fathom is inherently seated at the threshold of unfathomable territory.

Unimaginable, unfathomable, unforgettable is how I describe 2020.

From Time

Losing a blue-eyed son taught Nana that life can deliver unfathomable pain and yet life still stands, with some grace, on the other side.

The stock’s price reached a high of $483 this morning, up an unfathomable 12,000% from its $4 price around this time a year ago.

From Quartz

To some, the decision to help these patients may seem unfathomable—insane, even.

And yet, this almost-unfathomable plot somehow manages to elicit a sense of déjà vu.

Those of you who, for reasons unfathomable, are sober on this occasion may need it explained.

Dr. Gardere said he has seen first-hand the role faith has played in helping people recover from seemingly unfathomable setbacks.

That a woman could be intelligent, educated and CHOOSE to be a sex worker is almost unfathomable.

But still more wonderful were those great, dark, velvety eyes, deep and unfathomable.

Miss Horton looked up at him, and under her glance Sir Rowland felt that he was a man of unfathomable ignorance.

And lo, this Olympian being, this unfathomable man, descended from his cloud-capped heights and held out his hand to Tchaikovsky.

Those immense ridges are not only found rising out of the unfathomable deep.

Orme wondered at the unfathomable intelligence of those eyes.