Was troubled to catch Catholic taken in by belief that's above criticism (6,3)
I believe the answer is:
sacred cow
'above criticism' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'was troubled to catch catholic taken in by belief' is the wordplay.
'troubled' indicates an anagram.
'to catch' means one lot of letters goes inside another.
'catholic' becomes 'C' (abbreviation as in RC for Roman Catholic).
'taken in by' indicates putting letters inside.
'belief' becomes 'credo' (credo is a kind of belief).
'was' with letters rearranged gives 'saw'.
'c' going into 'credo' is 'credco'.
'saw' going around 'credco' is 'SACRED COW'.
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for sacred cow that I've seen before include "Institution seen as above criticism" , "One unreasonably held to be above criticism" , "Hallowed bovine in India or revered institution" , "lower in religion" , "one not to be criticised" .)