Ruler good, following relations (4)
I believe the answer is:
king
'ruler' is the definition.
(king is a kind of ruler)
'good following relations' is the wordplay.
'good' becomes 'g' (abbreviation).
'following' says to put letters next to each other.
'relations' becomes 'kin' (I've seen this before).
'g' put after 'kin' is 'KING'.
(Other definitions for king that I've seen before include "VIP" , "indispensable on board" , "Sovereign" , "initially unable to move" , "Male monarch" .)