From Middle English ruful, rewful, equivalent to rue + -ful.
rueful (comparative more rueful, superlative most rueful)
- Causing, feeling, or expressing regret or sorrow, especially in a wry or humorous way.
1986, John le Carré, A Perfect Spy:
- Merely, he received it with the rueful indulgence that he would show towards Tom when he came through with one of his solutions for ending world poverty or the arms race.
- Inspiring pity or compassion.
causing, feeling, or expressing regret or sorrow
inspiring pity or compassion