"Bunyip" is a word that originates from Australian Aboriginal culture, describing a mythical creature that inhabited waterholes and billabongs. If you're looking for synonyms for this uniquely Australian term, you might consider using terms like "water spirit," "water monster," or "aquatic creature." Other possible word choices for "bunyip" could include "lake monster," "river demon," or "swamp beast." In short, any term that conveys the idea of a mysterious, often terrifying creature that dwells in or near bodies of water could be used as a synonym for "bunyip." Keep in mind, however, that the term "bunyip" is often used specifically in relation to Australian folklore, and may not have a direct translation in other cultures.