cut the ground from under someone's feet
cut the ground from under(neath) (one's) feet
To suddenly cause problems for one. I plan to cut the ground from underneath the prosecutor's feet with this line of questioning.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
cut the ground from under someone's feetdo something which leaves someone without a reason or justification for their actions or opinions. informal
Farlex Partner Idioms Dictionary © Farlex 2017