Give half Canada weapons for the fleet (6)
I believe the answer is:
armada
'the fleet' is the definition.
(armada is a kind of fleet)
'give half canada' is the wordplay.
'give' becomes 'arm' (I can't explain this - if you can you should believe this answer much more).
'half' indicates taking half.
'canada' cut in half is 'ada'.
'arm'+'ada'='ARMADA'
'weapons for' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for armada that I've seen before include "Spanish war fleet" , "Navy" , "group of ships" , "A great fleet - Spain had one" , "Large war fleet" .)