What is "aileth"

Usage examples of "aileth".

He groaneth, He moaneth, He aileth, He waileth, Lying sighing, Nigh to dying, Oho, I know 'Tis so.

What aileth thee, O Wood-Sun, and is this a new custom of thy kindred and the folk of God-home that their brides array themselves like thralls new-taken, and as women who have lost their kindred and are outcast?

Cousin mine, what aileth thee, That art so pale and deadly for to see?

And the maiden bent down towards her, and said, "What aileth thee that thou answerest no one to-day?

It is but dretching of swevens, said Sir Bors, for I doubt not Sir Launcelot aileth nothing but good.