heretical
US /həˈret̬.ɪ.kəl/
UK /həˈret̬.ɪ.kəl/

1.
of or relating to heresy or heretics
:
•
The church condemned his heretical views.
•
He was accused of spreading heretical doctrines.
2.
holding an opinion at odds with what is generally accepted
:
•
His ideas on education were considered heretical by traditionalists.
•
To suggest such a thing would be almost heretical in this community.