Be jealous of (4)
I believe the answer is:
envy
'be jealous 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 "Wish for thing or quality belonging to another" , "Bad feeling" , "One of 7 vices" , "Resentful feeling" , "Jealous longing" .)