Contrary to, or offending against, the rules of propriety or good breeding; guilty of, or prone to, rude, unbecoming, or uncivil words or actions; as, an impertient coxcomb; an impertient remark
characterized by a lightly pert and exuberant quality; "a certain irreverent gaiety and ease of manner
If someone talks or behaves in a rather impolite and disrespectful way, you can say that they are being impertinent. Would it be impertinent to ask where exactly you were? = impudent, cheeky. rude and not respectful, especially to someone who is older or more important = cheeky
not pertinent to the matter under consideration; "an issue extraneous to the debate"; "the price was immaterial"; "mentioned several impertinent facts before finally coming to the point"
Not pertinent; not pertaining to the matter in hand; having no bearing on the subject; not to the point; irrelevant; inapplicable