(n.) One who truckles, or yields servilely to the will of another.

apple-polisher ass-licker backscratcher backslapper bootlick bootlicker brown-nose brownie clawback courtier creature cringer dupe fawner flatterer flunky footlicker groveler handshaker helot instrument jackal kowtower lackey led captain lickspit lickspittle mealymouth minion peon puppet serf slave spaniel stooge suck sycophant timeserver toad toadeater toady tool tufthunter yes-man