difficult to decipher
of, relating to, or written with this system of symbols
Undecipherable handwriting or secret symbol.
Any symbol used in this system; a hieroglyph.
A writing system of ancient Egypt, Minoans, Maya and other civilizations, using pictorial symbols to represent individual sounds as a rebus
Difficult or impossible to comprehend, fathom, or interpret.
One who or that which is inscrutable; a person, etc. that cannot be comprehended.