IPA: /kɒnˈtjuːmɪlɪəsli/
KK: /kɒnˈtjuːmɪlɪəsli/
In a way that is rude, disrespectful, or insulting towards someone.
He spoke contumeliously to his colleagues, showing no respect for their opinions.
Contumeliously → It is formed from "contumelia" (meaning insult or injury) and the suffix "-ously" (meaning in a manner). The word describes behaving in a manner that is insulting or disrespectful.
Think of 'contumelia' which means insult, and remember that 'contumeliously' describes acting in an insulting way.
No commonly confused words.