a mystery to (one)

Something that is difficult to understand. Why she walked out in such a huff this morning is a mystery to me! She was acting normally before that. It was a mystery to scientists where the birds migrated to until they banded some of them and tracked their movement.

Common Names:

Name	Pronounced	Usage
Adebowale	-	Western African, Yoruba
ÁLeifr	-	Ancient Scandinavian
Ray	RAY	English
Nika (2)	-	Slovene, Croatian
Haidee	HAY-dee (English)	Literature
Gisella	jee-ZEL-lah	Italian