difficult to ...; hard to ...
hard to say; inexpressible; hesitant to say; embarrassing; delicate
grateful; thankful; welcome; appreciated; evoking gratitude
unbearable; intolerable; unendurable
unbelievable; incredible; implausible
hard to get; hard to come by
beyond help; past salvation; incorrigible; irredeemable
hard-to-forgive; intolerable; inexcusable; unpardonable
value; worth; virtue; blessing
unshakable; immovable; undeniable
to be grateful; to feel grateful; to be thankful
unapproachable; inaccessible; difficult to access
unwelcome favor; unwelcome favour; misplaced kindness
thankfully; fortunately; luckily; mercifully
uncontrollable; irrepressible
unapprovable; unable to be confirmed
formidable; not to be sneered at; not to be made light of
to accept (a thing) with thanks
difficult to solve; intractable (problem)
hard to control; unmanageable
deep-rooted (suspicion, etc.)
difficult to say which of the two is better; hard to tell which is better; (there is) little to choose between them
hard to replace (with other person)
study hard while you are young; (lit.) boys grow old easily but getting learned is harder
there is no place like home; home is sweet to an exile
unable to decline; hard to refuse
hard to understand; hard to accept
illegible; indecipherable
difficult to translate; untranslatable
It is hard to explain; It is hard to say
both people are superb in skill (and thus it is hard to rank them)
one cannot live solely by oneself; one cannot accomplish anything solely by oneself; (lit.) clapping with one hand is hard
to be thankful; to feel grateful; to show one's gratitude