Sisyphean
arduous
backbreaking
dragging
exhausting
grueling
gruelling
hard
heavy
labor-intensive
labored
laborious
labour-intensive
laboured
leaden
operose
plodding
punishing
straining
strenuous
tiring
toilsome
wearing
wearying
24-month
3-second
all-composite
bimonthly
brain-stretching
fannish
formalin
glow
hygienic-dietetic
non-binding
non-decreasing
one-term
organization-wide
overanxiety
override
photosynthetic
rebels'
semicontinuous
sericultural
suboptimal
tragi-comic