Wiktionary
vb. (en-past of: youthen)
Usage examples of "youthened".
And she was the wrong age: not her real seventy six or her youthened sixteen.
The Magician was actually a very old man, youthened for this quest, and he had the experience and control of age.
I were youthened by sixty years, and there was surely reason for that.
It wasn't exactly uncertainty about their respective futures, though that helped, and not exactly that the youthened Magician Trent was pleasant company, though that also helped.
Maybe Trent's real age was making him senile, despite his greatly youthened body.
You baby-sat me when I had been youthened by overdosing on the water from the Fountain of Youth.
The dragon youthened rapidly, becoming smaller, with brighter green scales.
It had once been a full fountain, but had worn down into a more ordinary spring over the course of centuries, or perhaps the rocks around it had youthened into sand.