Girl in fleece produces weapon (6)
I believe the answer is:
cannon
'weapon' is the definition.
(cannon is a kind of weapon)
'girl in fleece' is the wordplay.
'girl' becomes 'Ann' (woman's name).
'in' indicates putting letters inside.
'fleece' becomes 'con' (I've seen this before).
'ann' going into 'con' is 'CANNON'.
'produces' is the link.
(Other definitions for cannon that I've seen before include "Gun - billiards' shot" , "Great gun" , "Wheeled guns" , "Snooker shot" , "Large gun that fires heavy shells" .)