Idioms and Phrases with dig one's own grave
dig one's own grave
Seriously harm oneself, cause one's own ruin or downfall. For example, If Sam pursues that course, he'll be digging his own grave. [First half of 1900s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.