When it comes to finding synonyms for the word "preterrestrial," there are a few options to consider. One option might be the word "extraterrestrial," which refers to something that is found outside of Earth. Another option could be "supernatural," which denotes something beyond the realm of what is considered natural or normal. Other potential synonyms might include "otherworldly," "transcendent," or "celestial," all of which suggest a sense of being otherworldly or beyond the earthly realm. Ultimately, the choice of synonym will depend on the context in which the word is being used and the specific connotation desired.