un·fath·om·a·ble
adjective/ʌnˈfæðəməbl/
/ʌnˈfæðəməbl/
(formal)- too strange or difficult to be understood
难以理解的；莫测高深的 - an unfathomable mystery
难以解释的奥秘 - We are confronted with the unfathomable nature of human motivation.
我们面临着人类动机的深不可测的本质。
- an unfathomable mystery
- if somebody has an unfathomable expression, it is impossible to know what they are thinking
（表情）难以琢磨的，微妙的