indecipherable

adjective

in·​de·​ci·​pher·​able ˌin-di-ˈsī-f(ə-)rə-bəl 

: incapable of being deciphered

indecipherable writing

an indecipherable message

indecipherably

ˌin-di-ˈsī-f(ə-)rə-blē 

adverb

Synonyms of indecipherable

• illegible

Examples of indecipherable in a Sentence

His handwriting is almost indecipherable.

after so many years the paper label in the drawer of the antique desk is indecipherable

Recent Examples on the Web

Two streetlamps engaged in a mute but luminous dialogue, an indecipherable Morse code, alluding to the silent exchanges and secret ciphers of strangers who meet there for their trysts. —Javier Montes, Artforum, 1 Jan. 2026

If the manual is indecipherable or nonexistent, which is often the case, a clear YouTube video or online guide can help. —Larry Magid, Mercury News, 25 Dec. 2025

Niontay’s style—his slurring, nasal voice that sometimes renders bars indecipherable—appears faster, blurrier, and more piercing. —Benny Sun, Pitchfork, 22 Dec. 2025

Moments later, the masked man entered the classroom and screamed something indecipherable. —Raven Brunner, PEOPLE, 14 Dec. 2025

Word History

First Known Use

1802, in the meaning defined above