King starts to expect downright victory (5)
I believe the answer is:
edwin
'king' is the definition.
(I know that Edwin is a king)
'starts to expect downright victory' is the wordplay.
'starts to' says to take the initial letters.
'victory' becomes 'win' (a win is a victory).
The first letters of 'expect downright' is 'ed'.
'ed'+'win'='EDWIN'
(Other definitions for edwin that I've seen before include "Anglo-Saxon King" , "boy" , "Sir - Landseer, artist" , "Fellow" , "ancient king" .)