Runons are long, unpunctuated sentences that break the rules of grammar and can be confusing to read. However, there are many synonyms that can be used to describe this common mistake, including sentence fragments, fused sentences, comma splices, and excessive coordination. All of these phrases refer to the same grammatical problem, but they each emphasize a different aspect of the issue. For example, sentence fragments focus on incomplete thoughts that are incorrectly presented as full sentences, whereas comma splices highlight the problem of using a comma to join two independent clauses. By understanding the nuances of each synonym, writers can better avoid runons and create clear, effective prose.