Indifference in course in outskirts of Aylesbury (6)
I believe the answer is:
apathy
'indifference' is the definition.
('apathy' can be a synonym of 'indifference')
'course in outskirts of aylesbury' is the wordplay.
'course' becomes 'path' ('path' can be a synonym of 'course'**).
'in' means one lot of letters goes inside another.
'outskirts of' says to hollow out the word (remove centre letters).
'aylesbury' with its middle taken out is 'ay'.
'path' put inside 'ay' is 'APATHY'.
'in' is the link.
(Other definitions for apathy that I've seen before include "Indifference - listlessness" , "Absense of interest or emotion" , "Indifferent quality" , "Lack of emotion and interest" , "Disinclination to shift" .)