The term SWIMMERS' AILMENT can be solved by the crossword solution EARACHE, which is a seven-letter word. EARACHE is a common ailment among swimmers due to the presence of water in the ear canal. It is caused by an infection or inflammation of the ear canal, and can be very painful. Symptoms include pain, itching, and discharge from the ear. Treatment usually involves antibiotics or other medications, and prevention includes wearing ear plugs while swimming.