There are numerous synonyms for the phrase "million dollar questions" that are often used in everyday conversations. Some of the popular alternatives include "puzzling problems," "crucial inquiries," "biggest mystery," and "critical queries." Other synonyms for the million dollar question include "enigmas," "mysteries," "burning issues," or "hot topics." These expressions all refer to questions or issues that are essential, pressing, or simply difficult to answer. In casual settings, people may also use idiomatic phrases like "the elephant in the room," "the big picture," or "the bottom line" to refer to the million dollar question. Overall, these synonyms are all useful in different contexts when trying to describe an important or challenging issue with a bit more nuance.