Interjectionally is an adverb that refers to something that is introduced abruptly or unexpectedly. Some common synonyms for interjectionally include suddenly, spontaneously, out of the blue, unexpectedly, surprisedly, and startlingly. Each of these words can be used to describe a situation where something unexpected or jarring occurs, such as a sudden loud noise or the sudden appearance of an object or person. Depending on the context, some other synonyms for interjectionally might include impulsively, unthinkingly, or impulsively. Ultimately, the choice of synonym will depend on the specific context in which the word is being used and the intended meaning and impact of the interjection.