I'd suggest "sycophant" (a "'yes' man." A "yes man" is a person who always answers "yes" to their supervisor's desires, whims, or decisions, even when they're wrong.
If you want to get a bit more informal, a "suck up" or a "kiss up," is a person who always tries to please a supervisor. Both terms are derogatory, because they imply kissing or sucking somebody's rear end.
A supervisor is a person higher-up in corporate hierarchy or rank. Imagine climbing a ladder, and a supervisor or boss is farther up on the ladder than you are. You would normally stay far enough behind to avoid bumping into that person's behind. A kiss up or a suck up would be willing to kiss that rear end.
That's where we come to the term that's even more derogatory: a "brown noser" describes a person who is such a kiss up or suck up that, using the ladder analogy, they're willing to crawl up the ladder of success, even if it means putting their face right in a supervisor's behind, and getting their excrement on their nose.