Causing, feeling, or expressing sorrow or regret.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "rueful" in a sentence
"In fact, it could be the kind of flop that folks around the blogosphere discuss in rueful tones."
"With wry insight, he views the Steins ensconced in rueful domesticity."
"Priscilla, in rueful remembrance of many trips to the dressmaker's."