Treat lightly, scoff at. For example, He said the other children all laughed at his jacket, or They stopped laughing at his theory when it proved to be correct. [Late 1300s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.