Available Definitions:
1) 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.
2) v. i. - To be affected with pain or uneasiness of any sort; to be ill or indisposed or in trouble.
3) n. - Indisposition or morbid affection.