Strongly desire to surrender weapon (7)
I believe the answer is:
longbow
'weapon' is the definition.
(I know that longbow is a type of bow)
'strongly desire to surrender' is the wordplay.
'strongly desire' becomes 'long' (to long for something is to desire it).
'to surrender' becomes 'bow' (bow can mean to surrender or give in).
'long'+'bow'='LONGBOW'
(Other definitions for longbow that I've seen before include "Robin Hood's weapon" , "Decisive weapon at Agincourt" , "missile-launcher" , "Weapon shooting arrows" , "Powerful wooden weapon used against the French at Agincourt" .)