The phrase "up wall" refers to a situation where someone is experiencing difficulty or frustration. There are several synonyms for this phrase, including "stuck", "blocked", "at a loss", and "up against a brick wall". These terms all describe a situation where someone feels like they are unable to make progress or find a solution to a problem. Other synonyms may include "confused", "overwhelmed", "flummoxed", and "puzzled". When facing a situation where you feel "up wall", it can be helpful to take a step back, reassess the situation and seek advice or assistance from others.