pain point
Matterhorn
mountain
toughie
lightning in a bottle
task
challenge
snorter
booger
pull teeth
sharp end
praemunire
daunting
mire
three-pipe problem
big deal
challengingly
superchallenge
testing
hard nut to crack
stumblingblock
tough nut to crack
multichallenge
hit
bring off
hairy
tough
killer
hard
situation
hard time
mission impossible
snag
difficulty level
get out
problem
trouble
rough sledding
nodus
difficultate
difficulty
mean
ambitious
unsimpable
queer someone's pitch
hard-set
run for one's money
mountain to climb
no picnic
see the dark side of the moon
make hard work of
bear
skittish
laborious
trickily
have a mountain to climb
overchallenge
complicated
brain-bending
head trip
hard going
wrestle
hardpressed
trying
enmesh
get into trouble
challenging
doo-doo
arduous
dilemma
shit
an old dog for a hard road
uphill
tough cookie
devil
rub
rub along
poser
rigour
torfer
dys-
hard yards
recalcitrant
boil the ocean
let
brainteaser
megachallenge
taxing
uneasy
try as one may
agonistic
bad boy
difficult
eke out