Word for unquestioning belief/opinion.... Doctrine? Ideology? [duplicate]

Solution 1:

Here's what you might want -

Dogma

: a principle or set of principles laid down by an authority as incontrovertibly true.

"The dogmas of faith"

(From Oxford)

Solution 2:

The word zealot comes to mind.

Zealot - a person who is fanatical and uncompromising in pursuit of their religious, political, or other ideals.