Cleric is equal to boy (6)
I believe the answer is:
parson
'cleric' is the definition.
(I've seen this in another clue)
'equal to boy' is the wordplay.
'equal' becomes 'par'.
'to boy' becomes 'son' (male child).
'par'+'son'='PARSON'
'is' is the link.
(Other definitions for parson that I've seen before include "Rector; clergyman" , "A rector or vicar" , "man of the church" , "Minister of religion" , "service provider" .)