conundrum
/kəˈnʌndrəm/noun
A puzzle or problem that is hard to solve.
Example sentences
- “Choosing between the two job offers was a real conundrum.”
- “How to pay for the new school remains a conundrum for the town council.”
Despite the Latin look, its origin is unknown, and the plural is plain 'conundrums'. Originally it meant a riddle answered with a pun.