A point source from which radiation is emitted.
"The sun acts as a radiant point source emitting intense energy into space."
In plain English: A radiant is an old-fashioned word for someone who looks very happy and healthy with bright, glowing skin.
"The radiant was the woman in charge who welcomed every guest with warmth."
Radiating light and/or heat.
"The fire left the rocks glowing radiant, emitting enough heat to warm our hands even from a distance."
In plain English: Radiant means shining with bright light and looking very happy or healthy.
"She looked radiant in her new wedding dress."
Usage: Use "radiant" to describe someone glowing with health or happiness, but avoid using it as a verb since the action of emitting light requires the noun form "radiate." Do not confuse this adjective with "radient," which is a common misspelling lacking standard dictionary recognition.
The word radiant entered Middle English directly from the Latin radians, which is the present participle meaning "emitting rays." It originally described something that was shining with light.