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Definition of unfathomable

unfathomable

/ʌnˈfæð.ə.mə.bəl/
un · fath · om · a · ble
Adverb:unfathomably
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unfathomable Lexical Profile

unfathomable Game Scores & Validity

• adjective

1

Incapable of being fully explored, understood, or comprehended.

Example

"For many astronomers, the sheer scale of the expanding universe remains almost unfathomable."

2

Impossible to measure the depth or extent of; extremely deep or vast.

Example

"The submersible descended slowly into the unfathomable trenches of the Pacific Ocean."

Synonyms
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Antonyms
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• Rhymes for unfathomable

• Nearby Words

unfashionably
unfasten
unfatherly
unfathomable
unfathomably
unfathomed
unfavorable

Word Origin & Etymology

Coined in the early 17th century from the prefix 'un-' and 'fathomable', derived from the Old English 'fæthm', originally meaning the length of two outstretched arms used by sailors to measure the depth of water.

Cite this Entry

Wordmom. (2026). Definition of Unfathomable. In Wordmom Dictionary. Retrieved Nov 3, 2026, from https://wordmom.com/dictionary/unfathomable
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