FAQs About the word closed books

Closed books

something beyond comprehension

mysteries,puzzles,secrets,challenges,conundrums,enigmas,head-scratchers,matters,mystifications,problems

No antonyms found.

closed (off) => shut, closed (down) => closed (down), close ranks => close ranks, close one's eyes to => turn a blind eye to, close one's doors to => close its doors to,