POLITE = You ARE well-mannered, civilized
COURTEOUS = Displaying good manners/showing thought or regard for others
So if I describe someone as polite, it's their trait of character; they're either polite or a primitive monkey. If I describe someone as courteous, it's because of the actions they display like opening a door for someone, paying for someone's mountain of food and booze, or listening before offering an opinion etc.
❗ However, in everyday English, we often substitute COURTEOUS with POLITE. So with polite, you can't really make a mistake.
There are collocations to learn where the words or not interchangeable:
👉🏻 Common courtesy =the expected thing to do
- it's common courtesy for a man to hold the door open for a lady
- In England it's common courtesy not to take your filthy shoes off when entering someone's house
👉🏻 Out of politeness = doing it for the reason of being polite
- I decided not to push that man in front of the bus out of politeness.
- I always say please and thank you out of politeness!