Page clergyman shortened (5)
I believe the answer is:
recto
'page' is the definition.
(recto is a kind of page)
'clergyman shortened' is the wordplay.
'clergyman' becomes 'rector' (rector is a kind of clergyman).
'shortened' means to remove the last letter.
'rector' with its last letter taken off is 'RECTO'.
(Other definitions for recto that I've seen before include "front of leaf" , "right page" , "The right-hand page or leaf of a book" , "Right-hand page of an open book" , "One page" .)