tipster
nounUK /ˈtɪp.stər/
US /ˈtɪp.stɚ/
A person who tells others which horse or team might win a race or game.
The tipster told us that the black horse would win the race.
OTHER MEANINGS
2. Someone who gives secret or inside information, often for money.
The police caught the tipster who leaked the plan.
3. A writer who gives advice on which horses to bet on.
He reads the racing tipster's column every morning.
4. A person who shares helpful hints or advice about a topic.
She is a gardening tipster who posts weekly videos.