IPA: /rɪˈbɛl.jəs.li/
KK: /rɪˈbɛl.jəs.li/
In a way that shows a desire to resist authority or control.
The teenager spoke rebelliously against the rules set by her parents.
Rebelliously → It is formed from "re-" (meaning again) and "bellare" (meaning to wage war). The word describes the act of waging war against authority or norms again, hence acting in defiance.
Think of 'waging war' ('bellare') against something 'again' ('re-') — that's why rebellious means acting against authority.