Failliet means bankrupt; faillissement means bankruptcy. You can often find announcements of bankruptcies in newspapers, and you can then find the corresponding court case in the court records in the provincial archives. These may give you an insight in the business relationships of your ancestor.

Personnel meeting at a bankrupt factory, informing them they would lose their jobs. Credits: Rob Croes, collection Nationaal Archief (CC-BY)
Another great article, Yvette. I actually did find a bankruptcy announcement for my great great grandfather. I’m interested to learn more about corresponding court records. How would one go about finding or accessing those records?
Thanks so much for all your wonderful information. Love your blog!
Leslie