IPA: /ˈreɪdiəntli/
KK: /ˈreɪdiəntli/
In a way that shines brightly or is full of light and happiness.
She smiled radiantly at the crowd during her speech.
Radiantly → It is formed from "radiant" (from Latin "radiantem", meaning shining or emitting rays) and the suffix "-ly" (meaning in a manner of). The word "radiantly" means in a manner that shines or emits light.
Think of something that shines brightly, as 'radiant' means to emit light, and '-ly' indicates the manner of shining.