1. reach a point where you are physically or mentally incapable of making further progress with something
hit a bit of a wall with something
The idiom to 'hit a wall' means to come to an obstacle or a mental barrier that is impossible to overcome or to get past. When you 'hit a wall' you are stuck at a particular point and find it hard to progress. To 'hit a wall' can also mean to become exhausted or so tired that you can not continue.