He declined the invitation snobbishly, saying that kind of party was beneath his taste.

snobbishly 是形容词 snobbish 的副词形式，由名词 snob（势利小人）加形容词后缀 -ish（具有...特性的）构成，再加上副词后缀 -ly。snobbish 意思是"势利的、自命不凡的"，snobbishly 表示"以势利的态度"。