I'm not sure how serious your question is, but you have pretty much defined a nonce word, which is a word invented for (and expected to be used only for) a special occasion; i.e., for the nonce. some nonce words surprise the inventor, catching on and thereby disqualifying themselves from the description.

then there is the phrase hapax legomenon [Gk, something said only once], a word evidenced by a single citation

(thus there is a distinction: a nonce word is identified by intent; a hapax is distinguished by evidence -- or lack thereof. :)

Thanks very much for that.

I meant the question in earnest *and* in silliness. As far as I can tell, there is often no distinction. This is supported, by a stretch, at the end of Kant's Third Critique. Having founded metaphysics on ethics (controversial, I'm sure) and embedded human being therein, he ends with two or three terrible jokes; the *structure* of his writing, at least, puts humor on the edge of the abyss and at the heart of being.

Here is another question: Is a word used once *in* the special occasion of a poem written for a single person a nonce word? At once, the occasion vanishes and is preserved, but the word remains as its remnant. (I know this all sounds like post-modern drivel; I'm only trying to be concise). Whether or not these words catch on, they both outlive *and* preserve the moment.

The notion of a hapax legomenon is similarly interesting. Considering the meaning of its Greek origin, can a hapax *be* a hapax? Can a word evidenced by a single citation *be* a word used once, or is its occurrence as evidence a second use, and the word a word used twice?