a self-serving flatterer
sycophant - flatterer
A ‘sycophant’ is a person who uses flattery and excessive obedience to win favour from others, particularly wealthy or influential people. This is usually done insincerely with the aim of securing personal advantage. The word is used as an insult.
Nobody ever says ‘no’ to that celebrity. She’s surrounded by sycophants.
Every time the boss made a joke, I could hear sycophantic laughter from certain people in the room.
When I’m interviewing a prominent political figure, I make sure to avoid sycophancy and remain objective.