(idiomatic) One who brownnoses; one who sucks up; a bootlicker, ass-kisser, sycophant.
Example: 1997 Ulrich Herbert, Hitler's foreign workers: enforced foreign labor in Germany under the Third Reich, Cambridge University Press, p126
A workmate reported the matter, "which is why the worker threatened to beat up the latter," calling him a "brownnose" and threatening to "wipe the floor with him."
2007 Felicity Young, An Easeful Death, Fremantle Press, p13
'I know, he's a natural brownnose. I guess he does have some talents.'
2010 Joseph Morse, Gods of Ruin: A Political Thriller, p46
You don't have to be such a brownnose, at least not to me.