difficult
disagreeable
hard
adverse
afflictive
analytic
annoying
antagonistic
arduous
backbreaking
besetting
bothersome
burdensome
conflicting
contrary
counter
counteractive
crushing
cut-and-try
demanding
detrimental
devitalizing
dispiriting
disquieting
distressing
draining
empirical
enervating
enfeebling
exacting
examinational
examinatorial
examining
exasperating
exhausting
exigent
experimental
explorational
explorative
exploratory
fact-finding
fatiguesome
fatiguing
feeling
frustrating
groping
grueling
harmful
heavy
hefty
heuristic
allying
applying
belying
buying
complying
crying
decrying
defying
denying
drying
dyeing
dying
eyeing
flying
frying
implying
indemnifying
lying
misapplying
overflying
overlying
plying
prying
relying
replying
retrying
shying
sighing
spying
supplying
tieing
tying
underlying
undying
vying