If you are fawning, you praise someone and act extra friendly, but it is not honest. You want them to like you, or to give you something — a better grade, a job, a favour. It often looks like too many compliments, laughing too hard at their jokes, or agreeing with everything they say. People fawn over bosses, famous people, and sometimes teachers. The word is not kind: it says the sweetness is fake, and a little embarrassing to watch. The usual pattern is “fawn over someone”; fawning also works as an adjective — fawning comments, a fawning smile. It is more a critical, grown-up word than a playground one. In casual talk a student might say “sucking up” or “kissing up” for the same idea. Though actually, showing respect is fine; fawning is respect that has gone oily.