Too much talk of a terror weapon (3)
I believe the answer is:
gas
'too much talk' is the definition.
'gas' can be an answer for 'talk' (I've seen this before). I am not certain of the 'too much' bit.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for gas that I've seen before include "It may be natural" , "Hydrogen or oxygen, say" , "Eg, nitrogen" , "Talk profusely" , "State of matter not solid or liquid" .)