crack a smile
Smile, as in Betty was a very serious person; she rarely cracked a smile. This colloquialism transfers crack in the sense of “break” to breaking a serious facial expression into a smile.
Words Nearby crack a smile
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
Browse