Understand cleric at church? To an extent (5)
I believe the answer is:
catch
'understand' is the definition.
(I've seen this before)
'cleric at church? to an extent' is the wordplay.
'to an extent' says the answer is hidden in the clue.
'CATCH' is hidden within 'cleric at church'.
(Other definitions for catch that I've seen before include "Good match" , "secure" , "Discover" , "(To) snare, net" , "Drawback that's not immediately evident" .)