impermanent
temporary
brief
brittle
capricious
changeable
corruptible
deciduous
diurnal
dying
episodic
evanescent
evergreen
fading
fickle
fleeting
flitting
fly-by-night
flying
fragile
frail
fugacious
fugitive
fungous
half-hardy
hardy
impetuous
impulsive
inconstant
insubstantial
momentary
mortal
mushroom
mutable
nondurable
nonpermanent
occasional
passing
perennial
perishable
short
short-lived
subject to death
temporal
transient
transitive
transitory
undurable
insect
delusive
earthly
fragmentary
frivolous
illusory
incidental
irrelevant
mundane
superficial
tenuous
trivial
uncertain
unreal
unsatisfactory
unsubstantial
femoral
eternal
lasting
long-lived