The term "most junctural" is relatively uncommon, and there are several synonyms that could be used to convey a similar meaning. One possibility is "critical", which suggests a highly significant or decisive point in time or space. Other options include "pivotal", "crucial", "vital", and "key", which all suggest an essential or central role in a particular situation. "Momentous" could also be used to convey the idea of a significant or life-changing event. Overall, there are many words that could be used to convey the idea of something being "most junctural", and the choice will depend on the specific context and nuances of the situation.