One given to singing about criminal business? (2,2)
I believe the answer is:
Here is my best explanation:
'criminal business?' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'one given to singing' is the subsidiary indication.
'one' becomes 'a'.
'given to' is a charade indicator (letters next to each other).
'singing' becomes 'tit' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'about' is the link.
(Other definitions for at it that I've seen before include "Active", "is busy", "engaged in dubious activity?", "Engaged in something particular", "occupied in a particular way", "Doing something", "engaged in crime?", "up to some criminal activity", "Occupied in some way" and "Up to no good".)