What do you use to filter out Bad Words for players names?


I am doing a 2player multiplayer game and players can name their own characters but I wanted to look into how I can prevent people from entering obscene or offensive words as their names.
We are using Gamesparks but they don’t have a feature for that yet so I was wondering if there were any other reliable and ideally free or low cost solutions?

Except for just sitting down one day and writing as many works I can think of in a text document. That would also only be in English.

What do you use?