This is the 4648th most frequent Polish word.
mur
Wall (typically a solid, tall, and strong structure).
In this sentence, 'mur' refers to a physical wall, a structure made of bricks.
Mur został zbudowany z cegieł.
The wall was built with bricks.
Here, 'mur' is used metaphorically to represent a barrier of emotions or feelings.
Mur nieufności między nimi zaczął się kruszyć.
The wall of distrust between them started to crumble.
In this sentence, 'mur' denotes defensive walls, typically surrounding and protecting a castle or fortress.