That co-worker at your part-time job who always compliments the boss and offers to do all kinds of little extra tasks is gnathonic. They’re trying to gain favor by flattery and fawning.
English has numerous words for people who will say and do just about anything to kiss up to the boss or someone who is wealthy or powerful. In the past, students looking to be a "teacher’s pet" would offer to shine the teacher's apple, and so were called apple polishers. A toady was someone who traveled with a touring showman and willingly ate a toad at his bidding as part of the act. And a sycophant (adjective form: sycophantic) is yet another word for a fawning person. Gnathonic comes from Gnatho, the name of a character in an ancient Roman play who flattered others.