The word "gassedup" is a slang term that means someone is hyped up or excited about something, often due to the use of drugs or alcohol. Some synonyms for this word might include strung out, wired, or geeked up. Other possibilities might include pumped, jazzed, or stoked. These words all convey a sense of heightened energy or enthusiasm, though they may not carry the same connotations of drug use or intoxication. Ultimately, the best synonym for "gassedup" will depend on the intended context and the specific nuances of the situation or conversation.