momentary

adjective3

1. •
   Lasting for only a moment.
2. •
   Ephemeral or relatively short-lived.

   • Tony's face expressed relief, and Nettie sat silent for a moment until the vicar said “It was a generous impulse, but it may have been a momentary one,[…].” — 1907
3. •
   (no longer used) Happening at every moment; perpetual.