nonword

[non-wurd]

noun

a word that is not recognized or accepted as legitimate, as one produced by a spelling or typographical error.
a word whose meaning or use is not approved in a given circumstance: “Failure” is a nonword in her vocabulary.

Origin of nonword

First recorded in 1960–65; non- + word

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018