Belief not affected by reversal (5)
I believe the answer is:
tenet
'belief' is the definition.
(synonyms)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for tenet that I've seen before include "A palindromic doctrine or creed" , "Article of faith; doctrine" , "Palindromic principle or belief" , "Canon" , "Fundamental belief" .)