Radiant means glowing brightly or shining with light and energy. The sun is radiant as it beams down on a summer day. A radiant smile lights up someone's whole face, making them look genuinely happy and full of life.

The word goes beyond just brightness: it suggests warmth and positive energy spreading outward. A radiant bride at her wedding doesn't just look happy, she seems to glow with joy that everyone around her can feel. When you're radiant with pride after accomplishing something difficult, that feeling shines through your expression and posture.

In science, radiant energy describes how heat and light travel outward from a source, like warmth radiating from a campfire. But most often, we use radiant to describe people who seem to shine from within, whether from happiness, health, confidence, or excitement. It's the difference between a polite smile and one that makes someone's eyes sparkle and their whole presence seem brighter.