entries in defineword.js gets overwritten with update Rated 5 out of 5 stars

great tool, but with every update my customizations that get stored in:
defaults\preferences\defineword.js
get overwritten.

That's a bug

If your customizations get overwritten with future versions, that is a bug that I'll need to look into. Do note that the very latest version does ignore your old settings because of a Mozilla requirement to store them in a new location.