Solitary confinement for international criminal (2,6)
I believe the answer is:
al capone
'criminal' is the definition.
(I've seen this before)
'solitary confinement for international' is the wordplay.
I cannot really see how this works, but
'solitary' could be 'one' (the only one) and 'one' is present in the answer.
'international' could be 'cap' (sportsperson who competes internationally) and 'cap' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for al capone that I've seen before include "Notorious Chicago gangster nicknamed Scarface" , "Famous gangster" , "US gangster in Chicago, arrested for tax evasion" , "criminal" , "Notorious gangster, d. 1947" .)