impertinent

If someone's rude without being openly nasty, like a kid in the back row of class quietly heckling his teacher, you can call him impertinent.

Impertinent originally meant just what it sounds like, "not pertinent, irrelevant," but it also came to mean "inappropriate, out of place" and therefore "intrusive, presumptuous; behaving without proper respect; insolent." It still carries a condescending air, so it's best used of or to a child being snippy to a grownup: "Don't be impertinent!" The stress is on the second syllable: im-PERT-inent.

Definitions of impertinent
  1. adjective
    improperly forward or bold
    impertinent of a child to lecture a grownup”
    synonyms: fresh, impudent, overbold, sassy, saucy, smart, wise
    forward
    used of temperament or behavior; lacking restraint or modesty
  2. adjective
    characterized by a lightly pert and exuberant quality
    synonyms: irreverent, pert, saucy
    spirited
    displaying animation, vigor, or liveliness
  3. adjective
    not pertinent to the matter under consideration
    “mentioned several impertinent facts before finally coming to the point”
    synonyms: extraneous, immaterial, orthogonal
    irrelevant
    having no bearing on or connection with the subject at issue
Word Family