Route inside a yard brings indifference (6)
I believe the answer is:
apathy
'indifference' is the definition.
(synonyms)
'route inside a yard' is the wordplay.
'route' becomes 'path' (synonyms).
'inside' indicates putting letters inside.
'yard' becomes 'y' (abbreviation).
'a'+'y'='ay'
'path' placed within 'ay' is 'APATHY'.
'brings' acts as a link.
(Other definitions for apathy that I've seen before include "Flatness" , "Absence of interest or emotion" , "Indifference - listlessness" , "Lack of interest or concern" , "Lack of excitement" .)