UNFATHOMABLE /ʌnˈfæðməbəl/ Scrabble 22 Words With Friends 26 Definition adjective of depth. adjective resembling an abyss in depth. — synonyms: abysmal, abyssal adjective incapable of being fully understood. Examples “The sheer numbers they attacked with were unfathomable.” See all 672 words you can make from UNFATHOMABLE → 12-letter words Words starting with U Words ending with E ← Unscramble different letters