gibberish
n.n. words or sounds that do not make sense because they are not real language. You use this when someone is speaking or writing in a way that is hard to understand.
n. nonsense or meaningless speech or writing. Often used to describe a string of words that lacks a logical structure or coherent meaning.
The old computer screen filled with gibberish.
The software crashed and started displaying a stream of gibberish instead of the actual data.
The encrypted file appeared as a series of random characters to the untrained eye, effectively rendering it as gibberish until the correct key was applied.
First attested mid-16th century. Origin obscure. Possibly from *gibber, of onomatopoeic origin imitating to the sound of chatter, possibly from or influenced by jabber, + -ish denoting the name of a language (compare English, Finnish, Spanish, etc.). The verb gibber, first attested circa 1600, is usually regarded as a back-formation from gibberish.