impudent, insolent, snotty-nosed, flip -- (marked by casual disrespect; "a flip answer to serious question"; "the student was kept in for impudent behavior")
fresh, impertinent, impudent, overbold, smart, saucy, sassy, wise -- (improperly forward or bold; "don't be fresh with me"; "impertinent of a child to lecture a grownup"; "an impudent boy given to insulting strangers"; "Don't get wise with me!")