Great office of strait-laced English clergyman (5,8)
I believe the answer is:
prime minister
'great office' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'strait-laced english clergyman' is the wordplay.
'strait-laced' becomes 'prim' (synonyms).
'english' becomes 'E' (abbreviation).
'clergyman' becomes 'minister' (minister is a kind of clergyman).
'prim'+'e'+'minister'='PRIME MINISTER'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for prime minister that I've seen before include "First Lord of the Treasury" , "May" , "Law once in UK" , "Leader 18 21" , "Head of state" .)