indecipherable

Indecipherable is an English adjective used to describe content that cannot be deciphered or understood. It can apply to handwriting that is not readable, but more often it refers to text, symbols, or systems of meaning that resist interpretation, even when they are visually legible. A message may be indecipherable because the cipher or code is unknown, the script is undeciphered, or there is insufficient context to determine its meaning.

The term is common in fields such as archaeology, linguistics, and cryptography, where researchers discuss inscriptions, scripts, or encoded messages that have not been successfully interpreted. In everyday language, indecipherable can describe ideas or arguments that are opaque or extremely difficult to grasp.

Etymology: indecipherable is formed from the prefix in- plus decipherable, meaning unable to be deciphered. It is distinct from illegible, which concerns readability and visual clarity, and from inscrutable or enigmatic, which refer to the apparent meaning being difficult to grasp.

Examples: The Voynich manuscript is widely regarded as indecipherable by contemporary experts, though not necessarily incomprehensible to all readers. Some ancient scripts, such as the Indus script, remain broadly indecipherable today.

See also: illegible, unreadable, inscrutable, undeciphered scripts, cryptanalysis.