Clergyman trailing king is always close (8)
I believe the answer is:
reverend
'clergyman' is the definition.
(synonyms)
'trailing king is always close' is the wordplay.
'trailing king' becomes 'r' (r is abbreviation for rex. I am not sure about the 'trailing' bit.).
'is always' becomes 'ever' (I've seen this before).
'close' becomes 'end' (I've seen this before).
'r'+'ever'+'end'='REVEREND'
(Other definitions for reverend that I've seen before include "Title of a Protestant clergyman" , "Title of respect for a member of the clergy" , "Clergyman's title" , "Title for clergyman or convent Mother" , "Vicar's title" .)