RUEFULLY
ruefully, contritely, remorsefully
(adverb) in a rueful manner; “‘I made a big mistake,’ he said ruefully”
Source: WordNet® 3.1
Etymology
Adverb
ruefully (comparative more ruefully, superlative most ruefully)
In a rueful manner; causing, feeling, or expressing regret or sorrow.
Synonyms
• sadly, sorrowfully, mournfully, regretfully
Source: Wiktionary
RUEFUL
Rue"ful, a.
1. Causing one to rue or lament; woeful; mournful; sorrowful.
2. Expressing sorrow. "Rueful faces." Dryden.
Two rueful figures, with long black cloaks. Sir W. Scott.
– Rue"ful*ly, adv.
– Rue"ful*ness, n.
Source: Webster’s Unabridged Dictionary 1913 Edition