The most common and most likely answer to this crossword clue is the 5 letter word CIVIL
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Buddy explains!
The straight part
We know that "polite" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case polite = civil.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CIVIL mean?
CIVIL adjective- Having to do with people and government office as opposed to the military or religion.
- Behaving in a reasonable or polite manner.
- Relating to private relations among citizens, as opposed to criminal matters.
- Secular.