Gibberish, jibberish, jibber-jabber and gobbledygook refer to speech or other use of language that is nonsense, or that appears to be nonsense. It may include speech sounds that are not actual words, or forms such as language games or highly specialized jargon that seems non-sensical to outsiders. Gibberish should not be confused with literary nonsense such as that used in the poem "Jabberwocky" by Lewis Carroll.
The word gibberish is more commonly applied to informal speech, while gobbledygook (sometimes gobbledegook, gobbledigook or gobbledegoo) is more often applied to writing or language that is meaningless or is made unintelligible by excessive use of abstruse technical terms. "Officialese", "legalese", or "bureaucratese" are forms of gobbledygook. The related word jibber-jabber refers to rapid talk that is difficult to understand.
The term gibberish was first seen in English in the early 16th century. Its etymology is not certain, but it is generally thought to be onomatopoeia imitative of speech, similar to the related words jabber (to talk rapidly) and gibber (to speak inarticulately).
Another theory is that gibberish came from the name of a famous 8th-century Islamic alchemist, Jābir ibn Hayyān, whose name was Latinized as "Geber." Thus, "gibberish" was a reference to the incomprehensible technical jargon used by Jabir and other alchemists.
Another theory, since discredited, asserts that it is derived from the Irish word gob or gab (mouth) or from the Irish phrase Geab ar ais (back talk, backward chat). The latter Irish etymology was suggested by Daniel Cassidy, whose work has been criticised by linguists and scholars. The terms geab and geabaire are certainly Irish words, but the phrase geab ar ais does not exist, and the word gibberish exists as a loan-word in Irish as gibiris.