Page on king and clergyman (6)
I believe the answer is:
rector
'clergyman' is the definition.
(rector is a kind of clergyman)
'page on king' is the wordplay.
'page' becomes 'recto' (recto is a kind of page).
'on' means one lot of letters go next to another.
'king' becomes 'r' (r is abbreviation for rex).
'recto'+'r'='RECTOR'
'and' acts as a link.
(Other definitions for rector that I've seen before include "Minister of religion" , "Head of some colleges" , "Churchman" , "Parson" , "Parish priest" .)