Weapon improvised by a god (5)
I believe the answer is:
shiva
'god' is the definition.
(Shiva is an example)
'weapon improvised by a' is the wordplay.
'weapon improvised' becomes 'shiv'.
'by' is a charade indicator (letters next to each other).
'shiv'+'a'='SHIVA'
(Other definitions for shiva that I've seen before include "Jewish period of mourning" , "God presiding over personal destinies" , "Hindu god, the destroyer" , "Major Hindu god with third eye in middle of forehead" , "powerful deity" .)