Intermissive is a relatively uncommon word that means intervening or interrupting. If you're looking for some synonyms for this word, there are a few different options you can consider. Some possible alternatives might include interruptive, disruptive, obtrusive, intrusive, or sporadic. These words all convey a sense of something coming between or breaking up a continuous flow or pattern, and they can be used in a variety of contexts to describe different types of things that might be causing this kind of disruption. Whether you're describing a flickering light or a distracting noise, these synonyms can help you find the right words to convey the right meaning.