IPA: /dɪsˈkɜːrtiəs/
KK: /dɪsˈkɜrtiəs/
Not showing respect or politeness; being rude to others.
It is considered discourteous to interrupt someone while they are speaking.
Discourteous → It is formed from "dis-" (meaning not) and "courteous" (from Old French *courtois*, meaning polite or refined). The word "discourteous" means not polite or lacking in courtesy.
Think of 'not' ('dis-') being added to 'polite' ('courteous') — that's why discourteous means not polite.