Killing a point with merriment (9)
I believe the answer is:
slaughter
'killing' is the definition.
(I know that slaughter is a type of murder)
'a point with merriment' is the wordplay.
'a point' becomes 'S' (South).
'with' means one lot of letters go next to another.
'merriment' becomes 'laughter' (I've seen this before).
's'+'laughter'='SLAUGHTER'
(Other definitions for slaughter that I've seen before include "Wholesale killing" , "Kill cruelly" , "Mass killing or carnage" , "Butchery" , "Widespread killing" .)