/snob/ , n.
1. a person who imitates, cultivates, or slavishly admires social superiors and is condescending or overbearing to others.
2. a person who believes himself or herself an expert or connoisseur in a given field and is condescending toward or disdainful of those who hold other opinions or have different tastes regarding this field: a musical snob.
[ 1775-85; orig. uncert; first used as a nickname for a cobbler or cobbler's apprentice, hence a townsman, someone of low class or lacking good breeding, commoner, hence someone who imitates persons of higher rank ]