The familiar insult is one branch of a much broader person word.
Old English ceorl could mean a man, a husband or a low-ranking freeman. Middle English cherl included non-noble people and insulting uses. Modern churl foregrounds rudeness.
The early domestic and rank meanings coexisted, and insulting uses were already present in Middle English.
Source
Merriam-Webster: churlWord History lists ceorl as man, married man and low-ranking freeman; cherl includes non-noble and ill-bred senses. The modern noun retains the rude-person meaning.