Sword pierced girl (7)
I believe the answer is:
cutlass
'sword' is the definition.
(type of sword)
'pierced girl' is the wordplay.
'pierced' becomes 'cut' (similar in meaning).
'girl' becomes 'lass' (lass can informally mean a girl).
'cut'+'lass'='CUTLASS'
(Other definitions for cutlass that I've seen before include "Sharp weapon" , "Curved sailors' sword" , "Short broad sword" , "Old sailor's weapon" , "Steel" .)