A number taking a weapon out of spite (6)
I believe the answer is:
malice
'spite' is the definition.
(synonyms)
'a number taking a weapon out' is the wordplay.
'a number' becomes 'L' (fifty in Roman numerals).
'taking' means one lot of letters goes inside another.
'weapon' becomes 'mice' (I can't explain this - if you can you should believe this answer much more).
'out' means one lot of letters goes inside another.
'a' inserted inside 'mice' is 'maice'.
'l' going into 'maice' is 'MALICE'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for malice that I've seen before include "Spitefulness" , "Hatred" , "Spite or spleen, perhaps aforethought" , "evil intent" , "Spiteful, animosity, sometimes a forethought" .)