The story
Blend of short + longevity. Or more precisely, from short + -gevity, a back-formation from longevity, specifically in the spoken form /lɒŋˈdʒɛvɪti/.
Etymology from Wiktionary, CC BY-SA 4.0.
shortgevity
Today it means: The state or condition of lasting for only a short period of time, in contrast to longevity. Full definition →