Weapon an American lawyer ships (6)
I believe the answer is:
armada
'ships' is the definition.
(group of ships)
'weapon an american lawyer' is the wordplay.
'weapon' becomes 'arm' (synonyms).
'an' becomes 'a'.
'american lawyer' becomes 'DA' (abbreviation for 'District Attorney').
'arm'+'a'+'da'='ARMADA'
(Other definitions for armada that I've seen before include "A great fleet, ships or planes" , "Spanish war fleet" , "Many ships" , "lot of craft" , "Fleet of armed ships" .)