A redeeming quality, especially one compensating for drawbacks or negative characteristics. For example, She may not be too knowledgeable, but her saving grace is that she doesn't pretend to be. This term, dating from the late 1500s, at first referred to the concept of being saved from eternal damnation, and was used more loosely only from the late 1800s on.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.