Work place hostility (10)
I believe the answer is:
opposition
'hostility' is the definition.
(thesaurus)
'work place' is the wordplay.
'work' becomes 'op' (abbreviation for opus).
'place' becomes 'position' ('position' can be a synonym of 'place'**).
'op'+'position'='OPPOSITION'
(Other definitions for opposition that I've seen before include "parliamentary group" , "obstruction" , "Rivalry" , "Political party" , "Resistance, dissent" .)