closed book, n.
something that baffles understanding and cannot be explained
<noun.cognition> freq. cnt.: 19 freq. cnt.: 18 freq. cnt.: 1
closed book enigma mystery secret
sample sentences
"how it got out is a mystery""it remains one of nature's secrets"
lexical pointers
derivationally related form
lexical pointers
derivationally related form
semantic pointers
hypernym