(adj.) Disrespectfully casual or
lighthearted,
particularly when someone or something is serious. Usually people behave
like this when they honestly couldn't care less about a situation.
Marie: "Did you see the way John
turned up at Uncle Freddy's funeral? He was wearing a
wifebeater, jeans, and
freaking pink slippers."
Joan:"That flippant prick! GEEZ!"