Clergyman is able to get on (5)
I believe the answer is:
canon
'clergyman' is the definition.
(canon is a kind of clergyman)
'able to get on' is the wordplay.
'able' becomes 'can'.
'to get' says to put letters next to each other.
'can'+'on'='CANON'
'is' acts as a link.
(Other definitions for canon that I've seen before include "Member of the clergy" , "set of books" , "Body of generally established principles for a given context" , "Such literary works are genuine" , "Principle; list of recognised works" .)