AIL, verb transitive To trouble; to affect with uneasiness, either of body or mind; used to express some uneasiness or affection, whose cause is unknown; as, what ails the man? I know not what ails him. What aileth thee, Hagar? Genesis 21:17. It is never used to express a specific disease. We never say, he ails a pleurisy; but it is unusual to say, he ails something; he ails nothing; nothing ails him. AIL, noun Indisposition, or morbid affection.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI