Criminal in poor health - for example, Capone? (7)
I believe the answer is:
illegal
'criminal' is the definition.
(similar in meaning)
'in poor health for example capone?' is the wordplay.
'in poor health' becomes 'i'll' (I've seen this in other clues).
'for example' becomes 'e.g.' (short for 'exempli gratia', 'for example' in Latin).
'capone?' becomes 'Al' (gangster Al Capone).
'ill'+'eg'+'al'='ILLEGAL'
(Other definitions for illegal that I've seen before include "Contraband" , "Outlawed" , "Prohibited by law" , "Not in conformity with law" , "Forbidden" .)