Remarkably rural pal uneasy with city (12)
I believe the answer is:
particularly
'remarkably' is the definition.
(thesaurus)
'rural pal uneasy with city' is the wordplay.
'uneasy with' indicates an anagram.
'rural'+'pal'='ruralpal'
'ruralpal' anagrammed with 'city' makes 'PARTICULARLY'.
(Other definitions for particularly that I've seen before include "in detail?" , "Very much" , "In a marked way" , "With special reference to" , "To an uncommon degree" .)