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]
What Is A “Self-Own”?There aren’t many better places, it seems, to celebrate the mistakes of others than on social media. Naturally, this is the arena where self-own has had great popularity. So, what does it mean?
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.