1 n-count The winner of a prize, race, or competition is the person, animal, or thing that wins it., (Antonym: loser)
She will present the trophies to the award winners...
2 n-count If you say that something or someone is a winner, you mean that they are popular and successful, or that they are likely to be popular and successful.
INFORMAL
(=success, hit) (Antonym: failure)
They think the appeal is a winner...