grateful; thankful; welcome; appreciated; evoking gratitude
unbelievable; incredible; implausible
hard-to-forgive; intolerable; inexcusable; unpardonable
unapproachable; inaccessible; difficult to access
uncontrollable; irrepressible
unapprovable; unable to be confirmed
formidable; not to be sneered at; not to be made light of
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)
hard to replace (with other person)
hard to understand; hard to accept