Skill of service in court (5)
I believe the answer is:
craft
'skill' is the definition.
(I know that craft is a type of skill)
'service in court' is the wordplay.
'service' becomes 'RAF' (Royal Air Force).
'in' means one lot of letters goes inside another.
'court' becomes 'ct' (abbreviation used in road names).
'raf' going within 'ct' is 'CRAFT'.
'of' is the link.
(Other definitions for craft that I've seen before include "Trickery" , "Cunning - ability" , "Workmanship" , "Cunning - vessels" , "Cunning in a well-built ship" .)