ephemericadj.
Etymology: < ephemer- (in ephemera adj. and n.1) + -ic suffix.Previous versions of the OED give the stress as: eˈphemeric.
1755 in S. Johnson
1847 in J. Craig ; and in mod. Dicts.
This entry has not yet been fully updated (first published 1891; most recently modified version published online June 2019).