Soldier obtained some lamb (5)
I believe the answer is:
gigot
'some lamb' is the definition.
(thesaurus)
'soldier obtained' is the wordplay.
'soldier' becomes 'GI' (term for US soldier).
'obtained' becomes 'got' ('get' can be a synonym of 'obtain').
'gi'+'got'='GIGOT'
(Other definitions for gigot that I've seen before include "Mutton or lamb leg" , "joint of meat" , "A bit of mutton" , "Perceive by touch" .)