Defeated leader disappears, having dined (5)
I believe the answer is:
eaten
'dined' is the definition.
(having had a meal)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for eaten that I've seen before include "used for food" , "Upset" , "This bread is soon forgotten, it's said" , "corroded" , "Swallowed" .)