The crossword solution for the term 'Feels Sick' is AILS, which is an acronym for Acute Illness Syndrome. This syndrome is a condition that is characterized by sudden onset of symptoms such as fever, chills, fatigue, and body aches. It can be caused by a variety of illnesses, including viral infections, bacterial infections, and even allergies. A person who is suffering from AILS may feel very sick and may need to seek medical attention.