sycophant

a person who tries to please someone in order to gain a personal advantage

An informer; a talebearer.

Greek sýkophантнs, lit. informer, slanderer

“I should best like to see these flung at her brother, the sycophant." "Do you know them?" asked Diodoros, hoarsely. "No," replied the old woman. "No need for that.”

— Georg Ebers, The Historical Romances of Georg Ebers

In Dhaka's bustling market, Ayodele spotted his sycophant, Stellan, fawning over a silk merchant. "Oh, sir, only the finest for you!" Stellan simpered. But when Ayodele bought cheaper goods, Stellan grumbled, "Sir, isn't that a bit common?" Ayodele smirked, knowing exactly how to play his groveling friend.

At the bustling Agege Market in Lagos, Cyrus eagerly followed Chief Olu's every nod and wave, his eyes never leaving the chief as he adjusted his cap and smiled wider with each of Olu’s gestures, a clear sycophant hoping to secure a prime spot for his wares tomorrow.

“To some psychologists, Wormtongue serves as an archetypal sycophant.”