Shocking weapon to put out by extremities of tower (9)
I believe the answer is:
traumatic
'shocking' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
(Other definitions for traumatic that I've seen before include "Direly shocking" , "Psychologically damaging" , "Emotionally shocking" , "Deeply distressing" , "Psychologically painful" .)