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
Sharyl	SHER-əl	English
Hieremias	-	Biblical Latin
&Aelig;Lfwig	-	Anglo-Saxon
Jolie	JO-lee (English), zho-LEE (French)	English, Various
Leilani	lay-LAH-nee	Hawaiian
Lenard	LEN-ərd	English