nonce-word [nɒns] n.
1.) A word invented "for the nonce," that is, for one occasion only. There are related terms such as nonce-borrowing (=a word borrowed from a foreign language only for one occasion), nonce-compound, nonce-expression, and nonce-meaning (Garner's Modern American Usage 3rd Edition).
Etymology: The first editor of the Oxford English Dictionary, James A. H. Murray (1837-1915), invented this expression for use in the Dictionary's entries.
"What's with voguism? The reader will ask: 'Is it a word? Why isn't it in my dictionary?' It is not synonymous with nonce-word, which is 'a term used once for some special occasion.' Rather, voguism is a not-so-new neologism that was created in this space in 1982. Though picked up and used once by Newsweek, the word has since languished, out of print and out of sorts" (The Right Word in the Right Place at the Right Time: Wit and Wisdom from the Popular "On Language" Column in The New York Times Magazine, William Safire (ed.), 2004).