- IPA: /ʌnˈfæðəməbəl/, /ʌnˈfæðməbəl/
- Impossible to fathom or understand.
- Synonyms: fathomless, incomprehensible, unintelligible, Thesaurus:incomprehensible
- Antonyms: explicable, intelligible, Thesaurus:comprehensible
- The sheer numbers they attacked with were unfathomable.
- Difficult to penetrate.
- Synonyms: impenetrable, impregnable
- Antonyms: penetrable, pregnable
- French: incompréhensible
- German: unfassbar, unermesslich
- Italian: insondabile, imperscrutabile, incomprensibile
- Russian: непостижи́мый
- Spanish: incomprensible
- French: insondable
- Spanish: insondable