ephemeral ephemeral /ɪˈfɛmɝəl/

adjective

1. () Lasting a very short time  ( fugacious , transient , transitory , ephemeral , passing , short-lived , here today and gone tomorrow [Informal] , here today gone tomorrow [Informal] )
   lasting a very short time
    The ephemeral joys of childhood
   the ephemeral joys of childhood
    A passing fancy
   a passing fancy
    Youth's transient beauty
   youth's transient beauty
    Love is transitory but it is eternal
   love is transitory but it is eternal
    Fugacious blossoms
   fugacious blossoms
   

noun

1. Anything short-lived, as an insect that lives only for a day in its winged form  ( ephemeral , ephemeron )
   anything short-lived, as an insect that lives only for a day in its winged form