blue moon
age
donkey's
grip
ages
imperishable
enduring
abiding
coon's age
crow's age
light year
years
with ages
dog's age
at length
inveterately
far
forever
lifetime
hot minute
superlong
eon
long as one's arm
longwhiles
until the cows freeze over
until the cows come home
donkey's ears
aeon
donkey's years
macro-
long
dolicho-
eternity
forever and a day
time out of mind
long-pending
long-span
durable
overlong
indestructible
undestroyable
perdurable
month of Sundays
hyperextended
yonks
sesquipedalian
longish
ultralong
dragging
long ass