Flatterer (noun)

1. A person who uses insincere or excessive compliments to gain favor or advantage.
2. A person who uses insincere or excessive compliments in order to gain favor or advantage, often at the expense of others.

Origin:

Flatter + -er.

Examples:

1. He was a flatterer, always seeking favor.
2. The flatterer was always trying to gain an advantage.
3. The flatterer was insincere.
4. He was a master flatterer.
5. The flatterer was always in the good graces of the king.