Couple of stupid people involved with paid killer (8)
I believe the answer is:
assassin
'paid killer' is the definition.
(I've seen this before)
'couple of stupid people involved' is the wordplay.
'couple of' says to double the letters.
'stupid people' becomes 'ass' (I can't justify this - if you can you should give a lot more credence to this answer).
'involved' becomes 'in' (to be involved in something is to be 'in' it).
'ass' duplicated is 'assass'.
'assass'+'in'='ASSASSIN'
'with' is the link.
Can you help me to learn more?
(Other definitions for assassin that I've seen before include "Booth, for example" , "I kill" , "Murderer (of prominent figure)" , "One making hits" , "Killer of famous person" .)