Second weapon grating (8)
I believe the answer is:
strident
'grating' is the definition.
(I've seen this before)
'second weapon' is the wordplay.
'second' becomes 's' (common abbreviation).
'weapon' becomes 'trident' (trident is a kind of weapon).
's'+'trident'='STRIDENT'
(Other definitions for strident that I've seen before include "Harsh, grating" , "Loud and harsh over tridents" , "giving views forcefully" , "With a loud, harsh voice" , "harsh noise" .)