Avaricious man in grey (6)
I believe the answer is:
greedy
'avaricious' is the definition.
(I know that avaricious can be written as greedy)
'man in grey' is the wordplay.
'man' becomes 'ed' (short for Edward).
'in' is an insertion indicator.
'ed' placed inside 'grey' is 'GREEDY'.
(Other definitions for greedy that I've seen before include "Grasping" , "Over-desirous of food" , "Overeating" , "Having eyes bigger than stomach!" , "Keen" .)