conundrum
noun [ C ] uk/kəˈnʌn.drəm/ us/kəˈnʌn.drəm/
难题；复杂的问题
a problem that is difficult to deal with
Arranging childcare over the school holidays can be a real conundrum for working parents. 对双职工家长来说，学校放假期间如何安排照看孩子是个大难题。
（常以双关妙语为答案的）谜语
a question that is a trick, often involving a humorous use of words that have two meanings