Substantivally is a word that refers to something that is essential or substantial. There are several synonyms for this word, including substantially, essentially, fundamentally, significantly, and indispensably. All of these words convey the same meaning and can be used interchangeably in most contexts. When describing something in a significant or fundamental way, these words can help elevate your language and make your writing more impactful. Whether you're writing an essay, article, or report, using one of these alternatives to substantivally can help you convey your message more effectively and make your writing more engaging.