There are a lot of flashcard sets available at quizlet.com. Most of them can easily be imported into WordQuiz and KWordQuiz.
Locate the set you are interested in on the Quizlet web site. When viewing a flashcard set click on the Export button at the top of the list.
Use Tab as the Word-Def Delimiter. Use New Line as the Def-Word Delimiter. Click Select All in the Data box. Copy to clipboard.
In (K)WordQuiz, create a new vocabulary and select Paste. The program will automatically calculate and add rows if needed.
Change the column titles and save the new vocabulary.