brick wall
An immovable, insurmountable, or unyielding obstacle or person. We tried to get in with our fake IDs, but the bouncer at the door is a brick wall. Ouch! I expected a soft landing, but that pile of snow was like a brick wall! How do you expect us to sneak into the dance with that brick wall of chaperones there?
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.