Proto-modern refers to the period of time just before and leading up to the modern era. Some words that could be used as synonyms for protomodern include pre-modern, transitional, emerging, or inchoate. These words all suggest a sense of change and progress, while still indicating a time preceding modernity. Other similar words might include nascent, burgeoning, or incipient. Overall, these words convey a sense of development and evolution, hinting at the exciting changes that were just around the corner as society moved from the protomodern to the modern era.