Philosopher working for detachment (7)
I believe the answer is:
platoon
'detachment' is the definition.
(thesaurus)
'philosopher working' is the wordplay.
'philosopher' becomes 'plato' (Plato is an example).
'working' becomes 'on'.
'plato'+'on'='PLATOON'
'for' is the link.
(Other definitions for platoon that I've seen before include "Group of soldiers" , "Soldiers under lieutenant" , "detail" , "Subdivision of a company" , "Military squad" .)