The advantage of vortaro.net is that as soon as you type something in the search field, it gives you word suggestions. If you begin to type muf immediately a list of words unfolds: mufi, mufo, mufli, etc. The final e in mufe clearly indicates the word is an adverb (mufi is a verb and mufo a noun). The important thing is to distinguish the root of the word, in this case muf. Other online dictionaries (like ReVo) don't have real-time suggestions, so you have to search different variations of the word based on the root in order to find it: mufe, mufa, mufi, mufo. In ReVo you will only find mufo. The advantage of ReVo is that it gives translations in other languages. In this case mufo is muff, a warm tubular covering for the hands. Accordingly, mufe ĉirkaŭanta is surrounding like a muff.