Anyway, it’s an article of faith (5)
I believe the answer is:
tenet
'an article of faith' is the definition.
(I've seen this before)
'anyway it's' is the wordplay.
'anyway' becomes 'tene' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'tene'+'t'='TENET'
Can you help me to learn more?
(Other definitions for tenet that I've seen before include "Teaching" , "Belief held as true" , "Canon" , "That's the law" , "Adiaphoron" .)