"Perfervidly" is a rare term that denotes an intense zeal or enthusiasm towards something. However, there are countless other words you can use to get across the same meaning. Some effective alternatives include ardently, passionately, fervently, fanatically, obsessively, feverishly, and excessively. These words convey the same level of intensity that perfervidly does, but may flow better in certain contexts. When writing, it is essential to keep a rich inventory of synonyms at your disposal. You can use them to vary your language, explain things more clearly, or emphasize certain points. So, take the time to discover and learn new words is vital to become a better writer.