Thought freedom found by outsiders in diocese (12)
I believe the answer is:
deliberation
'thought' is the definition.
(deliberation is a kind of thought)
'freedom found by outsiders in diocese' is the wordplay.
'freedom' becomes 'liberation'.
'found by' is a charade indicator (letters next to each other).
'outsiders in' says to hollow out the word (remove centre letters).
'diocese' with its centre taken out is 'de'.
'liberation' after 'de' is 'DELIBERATION'.
(Other definitions for deliberation that I've seen before include "Thinking about" , "decision-making process" , "Careful thought" , "circumspection?" , "discussion" .)