noun indisposition or morbid affection.
2. ail ·vi to be affected with pain or uneasiness of any sort; to be ill or indisposed or in trouble.
3. ail ·vt 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.