An error, esp one caused by bad judgment: Merkel's throw was the most renowned bonehead play in history(1910+ chiefly sports)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Examples from the Web for bonehead play
Historical Examples
And to think that he chose this moment to pull that bonehead play!