A word invented (usually unwittingly by subtracting an affix) on the assumption that a familiar word derives from it.

Roget 563: neology, neologism; newfangled expression, nonce expression; back-formation; caconym^†; barbarism.    archaism, black letter, monkish Latin.    corruption, missaying^†, malapropism, antiphrasis^†.    pun, paranomasia^†, play upon words; word play etc. (wit) 842; double-entendre [Fr.] etc. (ambiguity) 520; palindrome, paragram^†, anagram, clinch; abuse of language, abuse of terms.    dialect, brogue, idiom, accent, patois; provincialism, regionalism, localism; broken English, lingua franca; Anglicism, Briticism, Gallicism, Scotticism, Hibernicism; Americanism^†; Gypsy lingo, Romany; pidgin, pidgin English, pigeon English; Volapuk, Chinook, Esperanto, Hindustani, kitchen Kaffir.    dog Latin, macaronics^†, gibberish; confusion of tongues, Babel; babu English^†, chi-chi.    figure of speech etc. (metaphor) 521; byword.    colloquialism, informal speech, informal language.    substandard language, vernacular.    vulgar language, obscene language, obscenity, vulgarity.    jargon, technical terms, technicality, lingo, slang, cant, argot; St.    Gile's Greek, thieves' Latin, peddler's French, flash tongue, Billingsgate, Wall Street slang.    pseudology^†.    pseudonym etc. (misnomer) 565; Mr.    So-and-so; wha d'ye call 'em^†, whatchacallim, what's his name; thingummy^†, thingumbob; je ne sais quoi [Fr.].    neologist^†, coiner of words.    ... show more