Self-satisfied sixth contestant gets cup (4)
I believe the answer is:
smug
'self-satisfied' is the definition.
(synonyms)
'sixth contestant gets cup' is the wordplay.
'sixth contestant' becomes 's' (6th letter of 'contestant').
'gets' is a charade indicator (letters next to each other).
'cup' becomes 'mug' (I've seen this before).
's'+'mug'='SMUG'
(Other definitions for smug that I've seen before include "Arrogantly complacent" , "Self-righteously complacent" , "Self-satisfied about gums" , "goody-goody" , "Showing excessive self-pride" .)