Here’s why, we hear, it shouldn’t be believed (6)
I believe the answer is:
heresy
'it shouldn't be believed' is the definition.
The definition suggests a singular noun which matches the answer.
'here's why we hear' is the wordplay.
'we hear' indicates a 'sounds like' (homophone) clue.
'why' sounds like 'y'.
'heres'+'y'='HERESY'
Can you help me to learn more?
(Other definitions for heresy that I've seen before include "Unorthodox religious opinion" , "Opinion contrary to those of orthodox religion" , "Doctrine that differs from the orthodox position" , "Opinion contrary to accepted religious belief" , "Opinion contrary to generally accepted beliefs" .)