By the sound of it, weapon flew high (6)
I believe the answer is:
soared
'flew high' is the definition.
(I've seen this in another clue)
'by the sound of it weapon' is the wordplay.
'by the sound of it' shows a homophone (sound like).
'weapon' becomes 'sword' (sword is a kind of weapon).
'sword' is a homophone of 'SOARED'.
(Other definitions for soared that I've seen before include "Rose high into the air" , "Rose high in flight like bird" , "Flew upwards or high in the sky" .)