Killer at home with couple of fools (8)
I believe the answer is:
assassin
'killer' is the definition.
(I know that assassin is a type of killer)
'home with couple of fools' is the wordplay.
'home' becomes 'in' ('he's home' can mean 'he's in').
'with' is a charade indicator (letters next to each other).
'couple of' indicates the doubling of some letters.
'fools' becomes 'ass' (I can't explain this - if you can you should give a lot more credence to this answer).
'ass' duplicated is 'assass'.
'in' put after 'assass' is 'ASSASSIN'.
'at' acts as a link.
Can you help me to learn more?
(Other definitions for assassin that I've seen before include "I kill" , "Hired murderer" , "Killer of famous person" , "A killer of political or religious leader" , "butcher" .)