impertinent comes from Old French impertinent, from Late Latin impertinens ('not belonging'), from in- ('not') + pertinens ('pertaining'), from pertinere ('to relate to'). Morphologically, the prefixed shape matters: the initial element belongs to the recorded formation and helps explain the modern form's surface analysis. In present English, the adjective sense is "rudely bold or disrespectful; also irrelevant", so the historical development ends in a clearly identifiable modern dictionary use. The same base also appears in related forms such as pertinent, pertain, and appertain, and in derivatives such as impertinently and impertinence. Its semantic neighborhood includes impudent, insolent, rude, and disrespectful, which helps locate the modern sense without adding a separate etymological claim. The named historical forms include Latin impertinens and Latin pertinere.