Emily Dickinson Lexicon

AIL, v.t. [Sax. eglian, to be troubled, to be irksome; egle, trouble, grief. In the Saxon, it is impersonal.]

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? – Gen. xxi. It is never used to express a specific disease. We never say, he ails a pleurisy; but it is usual to say, he ails something; he ails nothing; nothing ails him.