From Longman Dictionary of Contemporary Englishunfathomableun‧fath‧om‧a‧ble /ʌnˈfæðəməbəl/ adjective literary MYSTERIOUStoo strange or mysterious to be understood
Examples from the Corpus
unfathomable• His expression was shuttered again, unfathomable.• His glance at her was unfathomable.• Whitton's and Fitzormonde's deaths at the Tower were still as unfathomable as ever.• The persistence of the image is as unfathomable as the alleged attributes of the people of the Celestial Empire themselves.• Night was the child of Chaos and so was Erebus, which is the unfathomable depth where death dwells.• They are a rigorous mystery, governed by unfathomable equations.• the unfathomable mysteries of human nature• The Liang family had passed those years in a strange, unfathomable netherworld.• They are unfathomable only to those who believe pax moderna to be the sole rational arrangement. 