Be covetous of (4)
I believe the answer is:
envy
'be covetous of' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for envy that I've seen before include "Jealous emotion - deadly sin" , "Resentment at another's success" , "Desire as a rival" , "Feeling of discontent" , "Wish for thing or quality belonging to another" .)