The antonyms for the word "longlived" are numerous, as there are many words that convey the opposite meaning of being long-lasting or enduring. Some of the common antonyms include fleeting, short-lived, ephemeral, transient, temporary, momentary, evanescent, and perishable. These words describe things that are not meant to last or endure, and which typically have a short life span. While longlived things endure for many years, the antonyms describe things that are inherently temporary and will fade away with time. In conclusion, understanding the antonyms for longlived provides insight into the brief nature of some things in life.