Urge, say, almost vanished (3,2)
I believe the answer is:
egg on
'urge' is the definition.
(to egg someone on is to urge them to do something)
'say almost vanished' is the wordplay.
'say' becomes 'eg' (both can mean for example).
'almost' means to remove the last letter (almost the whole word is kept).
'vanished' becomes 'gone' (gone can mean vanished or disappeared).
'gone' with its final letter taken away is 'gon'.
'eg'+'gon'='EGG ON'
(Other definitions for egg on that I've seen before include "Push" , "Fire" , "Prompt" , "Urge, impel" , "Urge (someone) to take risks" .)