Influxion is a relatively uncommon word, but there are plenty of synonyms that can be used in its place. Some of these include influx, flow, surge, deluge, inundation, onslaught, avalanche, and torrent. Each of these words refers to a large and sudden increase in something, whether that be people, ideas, or resources. Depending on the context, some synonyms may be more appropriate than others. For example, "influx" may be best used to describe a sudden surge of people to a particular location, whereas "avalanche" would be more fitting to describe a sudden influx of information or opinions. These synonyms can help to add variety and clarity to your writing.