Exporting Kindle Vocabulary Builder words into Anki for learning and flash card memorizing is very straight forward. Just follow a few steps as below.
Also see the blog from an experienced Anki user.
Step 1: Export your Kindle words using Kindle Mate
Select your words (all words, Mastered or Learning words or any list of words), and then use the pop-up menu Export to File…(Ctrl+S). Remember to choose Anki format in the ‘Save as type’ option in the Save File Dialog.
Step 2: Import your exported file using Anki
Open Anki, access File-Import from File menu, then select your exported file in the previous step:
In the next Import Dialog, please check ‘Allow HTML in fields’, which will enable the paragraph format tags in the file.
You are done. Now enjoy learning your Kindle words using Anki!