Go up to stop explosive weapon (7)
I believe the answer is:
trident
'weapon' is the definition.
(trident is a kind of weapon)
'go up to stop explosive' is the wordplay.
'go up' becomes 'ride' (riding is a kind of going up).
'to stop' means one lot of letters goes inside another.
'explosive' becomes 'tnt' (TNT is an example).
'ride' inserted inside 'tnt' is 'TRIDENT'.
(Other definitions for trident that I've seen before include "Submarine-launched ballistic missile" , "Spear with three prongs" , "spear carried at sea" , "Pronged spear" , "Neptune's weapon" .)