### Clue: Mercenary having dined heartily tucked into meat (5)
### Answer: VENAL 
 ### Explanation: Definition: Mercenary
 **Middle letter of**(… heartily) "dined" **contained in**(tucked into) VEAL(meat of a calf, used as food).
Defn: Open to being paid to do something dishonest or immoral.
A possible connection to 12 across.