Decorum – behaviours that people consider correct and polite
This person de-cores them (decorum) but I eat my apples the proper way, which is considered correct and polite.
Examples of decorum in a sentence
She was kicked out of the party because she had absolutely no decorum.
He had little understanding of the decorum expected at such a high class restaurant, and made an absolute fool of himself.
She was shocked at her dates lack of decorum and rude behaviour towards the waiters.