Explosive stuff (9)
'explosive stuff' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tnt that I've seen before include "Initially, powerful explosive" , "Type of high explosive" , "Explosive compound" , "Explosive stuff" , "Very powerful explosive, compressed" .)
(Other definitions for gelignite that I've seen before include "source of flare-up" , "Explosive used in mining" , "Tieing leg up in explosive" , "factor in altering mine?" , "High explosive" .)