Most certainly not involving king and country (6)
I believe the answer is:
norway
'country' is the definition.
(I know that Norway is a country)
'most certainly not involving king' is the wordplay.
'most certainly not' becomes 'no way' ('no way!' means 'definitely not!').
'involving' is an insertion indicator.
'king' becomes 'R' (abbreviation of Latin rex).
'noway' placed around 'r' is 'NORWAY'.
'and' acts as a link.
(Other definitions for norway that I've seen before include "Oslo is its capital" , "Now, Ray, go to the country" , "North European country" , "Edvard Munch's homeland" , "European kingdom" .)