brick wall

Short definition from Wiktionary

Noun

1. 1
   Used other than figuratively or idiomatically: see brick, wall. A wall made of bricks.
2. 2
   An obstacle.
3. 3
   A type of anti-aliasing filter with a steep cutoff.
4. 4
   Someone who is silent or unresponsive.

Verb

1. 1
   To build a brick wall around.
2. 2
   To filter using a brick wall filter.
3. 3
   To halt or limit abruptly.
4. 4
   To be uncooperative and unresponsive.