In The Meaning of Tingo, author Adam Jacot de Boinod admits that — in researching his book — he found many unusual foreign words that he could not, in the end, verify.
Two of my favorite of these unverified words were attributed to Japanese:
* Age-otori, which means ‘to look worse after a haircut’
* Ariga-meiwaku, which is ‘an act someone does for you that you didn’t want to have them do and tried to avoid having them do, but they went ahead anyway, determined to do you a favor, and then things went wrong and caused you a lot of trouble, yet in the end social conventions required you to express gratitude’.
*found this post at Rolf Pott's vagablogging.net