A little sycophantic weasel, a kiss-up, a brown-noser, the guy who does the dirty work for The Man. He (or she -- toadies come in all shapes, sizes, genders) is the person who rats out everyone in the office in the hopes of getting a promotion. They flatter the boss at every opportunity and will sabotage everyone else in the building to make sure they look good. They're future managers, which makes 'em even worse!

Here's an interesting thing: the word derives from "toadeater", a person who pretended to eat poisonous toads in order to show how effective a quack doctor's fake medicine was. Ya learn something new every day, don'tcha?