If you describe one person as the favourite of another, you mean that the second person likes the first person a lot and treats them with special kindness. Robert Carr, Earl of Somerset, a favourite of King James I The Prime Minister is no favourite of the tabloids
Your favourite thing or person of a particular type is the one you like most. a bottle of his favourite champagne Her favourite writer is Hans Christian Andersen. Favourite is also a noun. The Liverpool Metropole is my favourite. If you refer to something as an old favourite, you mean that it has been in existence for a long time and everyone knows it or likes it. Everyone must be familiar with the old favourite among roses, Crystal Palace
The favourite in a race or contest is the competitor that is expected to win. In a team game, the team that is expected to win is referred to as the favourites. The Belgian Cup has been won by the favourites F.C. Liege