Not decipherable; impossible to decode, read, understand or comprehend. (adjective)
Examples of word indecipherable
The characters are empty stereotypes, who often behave in indecipherable ways, and the dialogue is so awful it made me laugh out loud at least four or five times.
(Sorry Tommy, an increase in indecipherable gibberish doesn’t cut it!).
Her expression was indecipherable, her features refusing to relate to each other in a meaningful way.
I have lately been led to reflect a little, (for, now that I am growing old, my work has become [word indecipherable] special) on the artificial checks, but doubt greatly whether such would be advantageous to the world at large at present, however it may be in the distant future.
(Those who think you can get around that with a VPN or other purposes just need to remember that service providers can add jitter and such that will make calls indecipherable without affecting other sorts of data transmission.)