IPA: /dɪˈfaɪəntli/
KK: /dɪˈfaɪəntli/
In a way that shows resistance or bold disobedience.
She spoke defiantly, refusing to back down from her beliefs.
Defiantly → It is formed from "defiant" (from Latin "defiāre", meaning to renounce or to disobey) and the suffix "-ly" (meaning in a manner of). The word "defiantly" means in a manner that shows resistance or disobedience.
Think of someone acting in a way that shows they are 'renouncing' authority — that's why 'defiantly' means behaving in a resistant manner.