(1):
(v. i.) To be affected with pain or uneasiness of any sort; to be ill or indisposed or in trouble.
(2):
(v. t.) To affect with pain or uneasiness, either physical or mental; to trouble; to be the matter with; - used to express some uneasiness or affection, whose cause is unknown; as, what ails the man? I know not what ails him.
(3):
(n.) Indisposition or morbid affection.