Navy member, a lawyer (6)
I believe the answer is:
armada
'navy' is the definition.
(I've seen this before)
'member a lawyer' is the wordplay.
'member' becomes 'arm' (arm is a kind of member).
'lawyer' becomes 'da' (D.A. is an example).
'arm'+'a'+'da'='ARMADA'
(Other definitions for armada that I've seen before include "Large number of ships (Spanish?)" , "Spanish war fleet" , "Large war fleet" , "Naval fighting force" , "sea-borne unit" .)