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
Georgiana	jor-JYAH-nə, jor-JAY-nə	English
Shantelle	shahn-TEL, shan-TEL	English (Rare)
Fabianus	-	Ancient Roman
Paavali	PAH:-vah-lee	Finnish
Jockie	-	Scottish
Euphranor	-	Ancient Greek