adj
unfathomable
uhn-FA-thuh-muhbl
Unfathomable (adj) means So deep that it cannot be measured. Example: “The submarine descended into the unfathomable darkness of the trench.”
adj
1
So deep that it cannot be measured.
"The submarine descended into the unfathomable darkness of the trench."
2
Impossible to fully understand or grasp.
"Her grief after the loss was unfathomable to those who hadn't experienced it."
"The scale of the universe is almost unfathomable."
How to use unfathomable
Learner’s notesIn plain EnglishToo deep, vast, or complex to measure or understand.
Memory tip
Think of "fathom" as a unit for measuring water depth — "unfathomable" is literally "can't be measured," used mostly for ideas or feelings that are too huge to grasp.
Trace the full origin ↓
Common pairings
unfathomable depths
unfathomable grief
unfathomable mystery
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Word forms
- Comparative
- more unfathomable
- Superlative
- most unfathomable
Fill the gap
Can you complete this real example?
The submarine descended into the _____ darkness of the trench.
Etymology
From un- + fathom (originally, to measure the depth of water) + -able.
Synonyms
View more →Antonyms
fathomable
Related words
Rhymes for unfathomable
See all rhymes for unfathomable →Frequently asked questions
What does “unfathomable” mean?
The word “unfathomable” means so deep that it cannot be measured. In plain terms, too deep, vast, or complex to measure or understand.
How do you pronounce “unfathomable”?
“Unfathomable” is pronounced uhn-FA-thuh-muhbl (/ˌʌnˈfæð(ə)məb(ə)l/ in IPA).
How do you use “unfathomable” in a sentence?
Here is “unfathomable” used in a sentence: “The submarine descended into the unfathomable darkness of the trench.”
What part of speech is “unfathomable”?
“Unfathomable” is an adjective.
How many meanings does “unfathomable” have?
“Unfathomable” has 2 distinct senses listed in this dictionary. The most common is: so deep that it cannot be measured.
