Hostility over parking place (10)
I believe the answer is:
opposition
'hostility' is the definition.
(thesaurus)
'over parking place' is the wordplay.
'over' becomes 'o' (cricket abbreviation).
'parking' becomes 'p' (abbreviation on road signs).
'place' becomes 'position' (synonyms).
'o'+'p'+'position'='OPPOSITION'
(Other definitions for opposition that I've seen before include "Rivalry" , "those out of power" , "obstruction" , "antagonism" , "parliamentary group" .)