Explosive stuff
'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" .)