Refulgent...

So, I already knew the word effulgent from Buffy. It means shining. I looked it up. And today I'm reading this YA book - not even a terribly *good* one, and the girl goes along the whole book with her teenage superhero problems and hardly worries about school or grades at all, and then suddenly at the end she pulls out the word refulgent like it's a perfectly normal word for an adolescent to have at the tip of their tongues. Well, some adolescents, maybe, but the author hadn't previously impressed me with the depth of her character's vocabulary. Refulgent also means shining, in case you're wondering. I looked that one up too, just in case.

Is this actually another inchoate situation? Are these really commonplace words, and I'm behind the curve here? (Next I'll find out everybody's known the word contumely forever as well!)