The term 'difficult question' can be described in three ways: as a TOUGHIE (7 letters), a POSER (5 letters), or a STUMPER (7 letters). A TOUGHIE is a difficult problem or question that requires a lot of thought and effort to solve. A POSER is a difficult question or problem that is hard to answer or solve. A STUMPER is an especially difficult question or problem that is hard to answer or solve. All three terms refer to a difficult question or problem that requires a great deal of thought and effort to solve.