Appertinent :: Appertinent (n.) That which belongs to something else; an appurtenant.
Impertinent :: Impertinent (a.) Not pertinent; not pertaining to the matter in hand; having no bearing on the subject; not to the point; irrelevant; inapplicable.
Impertinent :: Impertinent (a.) 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..
Pertinent :: Pertinent (a.) Belonging or related to the subject or matter in hand; fit or appropriate in any way; adapted to the end proposed; apposite; material; relevant; as, pertinent illustrations or arguments; pertinent evidence..