brown noser

Etymology
A metaphorical image: when kissing the buttocks of another person, one's nose is liable to be covered in brown feces.

Noun

 * 1)  One who brownnoses (flatters or humors somebody in an obsequious manner for personal gain); one who sucks up; a bootlicker, ass-kisser, sycophant.

Synonyms

 * See also Thesaurus:sycophant
 * See also Thesaurus:sycophant