Translation of fiend in Spanish

I will add a feature to the dictionary builder tool, that marks a word as vulgar. The words that are shown in the tool are words that users did not find in our dictionary and a lot of them are vulgar.
I wanted to ask whether you would like to help in another English - Spanish project. The dictionary has around 10,000 -20,000 entries and many of them do not have sample sentences. We need to add sentences to give users more background.
It's very good that you can learn English with the help of technology (Internet), I think you'll learn quickly. Although I am now getting better, I feel the improvement. But once again I lack vocabulary.