be beyond (someone's) ken

if a particular subject is beyond your ken, you do not understand it or know much about it.

Don't talk to me about finance - it's beyond my ken.

Most of Derrida's work is beyond the ken of the average student.

• a big mouth
• a big noise
• a big shot
• a big wheel
• a billet-doux
• a bird-brain
• a bird in the hand
• a bird in the hand is worth two in the bush.
• a bird's eye view
• a bite of the cherry
• a bite to eat
• a bit much
• a bit of all right
• a bit of fluff
• a bit of how's your father
• a bit of rough
• a bit of skirt
• a bit on the side
• a bitter pill
• a bitter pill to swallow
• a bit too much
• a black day
• a black mark
• a blank cheque
• a blast from the past