The term 'difficult to describe' can be described by the crossword solutions of ELUSIVE (7 letters), HARD (4 letters), NAMELESS (8 letters), NEBULOUS (8 letters), and LIMN (4 letters). ELUSIVE means HARD to find or capture, while HARD implies something that is difficult to do or accomplish. NAMELESS suggests something without a name, and NEBULOUS implies something vague or unclear. Finally, LIMN means to describe or portray in words. Together, these words allude to something that is difficult to describe.