Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English


English definition of “unfathomable”


adjective     /ʌnˈfæð.ə.mə.bl̩/ formal
impossible to understand: For some unfathomable reason they built the toilet next to the kitchen.Difficult to understandComplicated and difficult to doPuzzle and confuse unfathomably     /-bli/ adverb formal
(Definition of unfathomable adjective from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
Focus on the pronunciation of unfathomable

Translations of “unfathomable”

Word of the Day


If you crew a boat, or crew for someone on their boat, you help to sail it.

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More