Short-lived means lasting only a brief time before ending or disappearing. When something is short-lived, it exists, thrives, or matters for a much shorter period than you might expect or hope.

A mayfly's entire adult life is short-lived: it lives for just a single day. Your excitement about snow might be short-lived when you remember you still have homework to finish. A friendship can be short-lived if one person moves away after just a few months. A new fad at school, like a particular game or phrase everyone suddenly uses, often proves short-lived when something newer replaces it within weeks.

The word captures a sense of something ending too soon. A short-lived victory means you won, but your success didn't last long. A short-lived rebellion might mean students convinced their teacher to cancel a quiz, but the next day she assigned two more.

Notice that short-lived doesn't tell you exactly how short: it depends on context. For a civilization, short-lived might mean a few centuries. For your enthusiasm about cleaning your room, short-lived might mean about five minutes. The key is that whatever it describes didn't last as long as it could have or should have.