Give weapons to girl in fleet (6)
I believe the answer is:
armada
'fleet' is the definition.
(I know that armada is a type of fleet)
'give weapons to girl' is the wordplay.
'give weapons to' becomes 'arm' (I've seen this in another clue).
'girl' becomes 'Ada' (girl's name).
'arm'+'ada'='ARMADA'
'in' acts as a link.
(Other definitions for armada that I've seen before include "1588 sea battle" , "group of ships" , "Fleet Drake defeated" , "Large number of ships (Spanish?)" , "Large war fleet" .)