It's criminal to take a couple of fools in (8)
I believe the answer is:
assassin
'it's criminal' is the definition.
I can't tell whether this defines the answer.
'to take a couple of fools in' is the wordplay.
'a couple of fools' can mean two replacements for 'fool'.
'to take' is an insertion indicator (inserted letters are taken in).
'fool' becomes 'ass' (both can mean a stupid person).
'fool' becomes 'ass' (both can mean a stupid person).
'ass'+'in'='assin'
'ass' inserted inside 'assin' is 'ASSASSIN'.
Can you help me to learn more?
(Other definitions for assassin that I've seen before include "Terrorist" , "One murders for political or monetary reasons" , "butcher" , "Political murderer" , "Hired murderer" .)