Follow mother's conviction (5)
I believe the answer is:
dogma
'conviction' is the definition.
(thesaurus)
'follow mother's' is the wordplay.
'follow' becomes 'dog' (I've seen this before).
'mother' becomes 'ma' (Ma is another word for mother or mum).
'dog'+'ma'='DOGMA'
(Other definitions for dogma that I've seen before include "Set of principles laid down as incontrovertibly true" , "Principles laid down by authority as true" , "Body of creed" , "Non-evidence based opinion" , "Some believe it certainly" .)