The crossword solution for the term 'difficult exam' is ORAL, which is a four-letter word. An ORAL exam is an assessment of a student's knowledge or skills that is conducted by speaking rather than writing. ORAL exams are often used to test a student's ability to think on their feet and to assess their understanding of a subject. They can be particularly difficult because they require students to answer questions in real-time without the benefit of being able to look up answers or take notes.