unreadablecipher
nounUK /ʌnˈriːdəbəl ˈsaɪfə/
US /ʌnˈriːdəbəl ˈsaɪfər/
A secret code that is too hard for anyone to figure out.
The spy found an unreadablecipher written in tiny symbols on the old map.
RELATED WORDS
OTHER MEANINGS
2. Writing so messy that no one can read it.
His homework was an unreadablecipher of scribbles and crossed-out words.
3. A message meant to hide its meaning from everyone.
The letter looked like an unreadablecipher until we found the key.
4. Something confusing that is hard to understand.
The instructions were an unreadablecipher to the new players.