When off sick, idle about with some rogue (7)
I believe the answer is:
villain
'some rogue' is the definition.
(both can mean a dishonourable person)
'when off sick idle about' is the wordplay.
'when off sick' becomes 'ill' (I am not sure about this - if you are sure you should believe this answer much more).
'idle' becomes 'vain' (I've seen this in another clue).
'about' indicates putting letters inside.
'ill' put within 'vain' is 'VILLAIN'.
'with' is the link.
Can you help me to learn more?
(Other definitions for villain that I've seen before include "Evil character" , "Criminal, rogue" , "Evil-doer" , "He may rob you" , "One played badly" .)