Title ultimately associated with this country, way back (7)
I believe the answer is:
dukedom
'title' is the definition.
(I have seen 'Hereditary title ' mean 'dukedom' so perhaps 'title' could also mean 'dukedom')
'ultimately associated with this country way back' is the wordplay.
'ultimately' suggests the final letters.
'with' is a charade indicator (letters next to each other).
'this country' becomes 'UK' (United Kingdom).
'way' becomes 'mode' (synonyms).
'back' shows that the letters should be reversed in order.
The last letter of 'associated' is 'd'.
'mode' in reverse letter order is 'edom'.
'd'+'uk'+'edom'='DUKEDOM'
(Other definitions for dukedom that I've seen before include "Hereditary title" , "Noble rank" , "Noble's position" , "nobility?" , "Wellington's rank" .)