A Catholic cleric is exact (8)
I believe the answer is:
accurate
'exact' is the definition.
(associated in meaning)
'a catholic cleric' is the wordplay.
'catholic' becomes 'C' (abbreviation as in RC for Roman Catholic).
'cleric' becomes 'curate' (I've seen this before).
'a'+'c'+'curate'='ACCURATE'
'is' is the link.
(Other definitions for accurate that I've seen before include "Factual" , "Correct in all details" , "Meticulous" , "Correct, right" , "Spot-on" .)