Good thing that comes to those who wait? (3)
I believe the answer is:
tip
'good thing that comes to those who wait?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tip that I've seen before include "Small amount" , "Empty" , "expected by those who wait" , "Overbalance; point" , "offered at end of repast" .)