Final answer:
The antonym of 'churlish' is 'polite', as it directly opposes the meaning of being rude or surly.
Step-by-step explanation:
The antonym for "churlish" is polite. The word 'churlish' describes someone who is rude, surly, or lacking in civility. Therefore, when looking for an antonym, you'd select an option that conveys the opposite meaning, which would be behavior that is considerate and shows good manners, as captured by the word 'polite'.