Shea reports that the term can be traced back to an article in the 1891 Fort Worth Gazette in which the paper printed the line "…it is the first declaration of how the party stands, and in great measure a refudiation of the charges of dickering…" It also cropped up again in 1925, in a headline entitled "Scandal Taint Refudiated In Teapot Case by Court, Fall Says in Statement."
But even though its use is widespread, She explains, it's still an open question whether "refudiate" will make its way permanently into the dictionary:
It may be the linguistic mayfly that attracts our attention for but a short burst of time and then becomes just another fad we look back upon. But candidates for Word of the Year need not have the promise of permanence - they are contending to be the word of this past year, and not necessarily every year to come.
[H/T: Morning News]