Philosopher has nothing new for group of soldiers (7)
I believe the answer is:
platoon
'group of soldiers' is the definition.
(type of military subdivision)
'philosopher has nothing new' is the wordplay.
'philosopher' becomes 'plato' (Plato is an example).
'has' means one lot of letters go next to another.
'nothing' becomes 'O' (O resembles 0).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'plato'+'o'+'n'='PLATOON'
'for' is the link.
(Other definitions for platoon that I've seen before include "Army unit" , "detail" , "Military squad" , "Team under lieutenant" , "Group under lieutenant" .)