A metaphysical conundrum, or a philosophical problem that is difficult to solve, can be described in various ways using a range of synonyms. For instance, it can be referred to as a puzzle, enigma, puzzle, paradox, or riddle. Other synonyms for the term can include a perplexity, a dilemma, or a puzzle that requires deep thought and analysis to solve. Other words that could be used to describe a metaphysical conundrum include a quandary, a mystery, or a conundrum that is perplexing and requires a great deal of contemplation to decipher. Overall, there are several words that can be used to describe the complexity of metaphysical conundrums and their difficult nature.