short
annual
biannual
biennial
bimonthly
biweekly
brief
brittle
capricious
catamenial
centenary
centennial
changeable
corruptible
daily
decennial
deciduous
diurnal
dying
ephemeral
evanescent
fading
fickle
fleeting
flitting
fly-by-night
flying
fortnightly
fragile
frail
fugacious
fugitive
hasty
hebdomadal
hourly
immediate
impermanent
impetuous
impulsive
inconstant
instant
instantaneous
insubstantial
lightning-like
menstrual
momentaneous
momently
monthly
mortal
mutable
continual
inward
mental
profound
sudden
temporary