1. (a.) Beginning and ending in a day; existing only, or no longer than, a day; diurnal; as, an ephemeral flower.

2. (a.) Short-lived; existing or continuing for a short time only.

3. (n.) Anything lasting but a day, or a brief time; an ephemeral plant, insect, etc.

brief brittle capricious changeable corruptible deciduous dying episodic evanescent evergreen fading fickle fleeting flitting fly-by-night flying fragile frail fugacious fugitive half-hardy hardy impermanent impetuous impulsive inconstant insubstantial momentary mortal mutable nondurable nonpermanent passing perennial perishable short short-lived subject to death temporal temporary transient transitive transitory undurable unenduring unstable volatile