be beyond (one's) ken

To be advanced beyond one's ability to understand or make sense of the subject matter or task at hand. The stuff they're teaching in this advanced math class is beyond my ken.

Common Names:

Name	Pronounced	Usage
Kortney	KORT-nee	English (Modern)
Kristopher	KRIS-tə-fər	English
&Thorn;Unor	-	Anglo-Saxon Mythology
Bryony	BRIE-ə-nee	English (Rare)
Gormflaith	-	Irish
Lital	-	Hebrew