A default happens when a lender decides you're not going to be able to pay back what you've borrowed.
This can be because you missed too many payments or don't make your payments in full. A default usually means that your account is closed and will remain on your report for 5 years.
How does this affect your score
Defaults can affect your credit score negatively. They show that you're not reliable when it comes to paying back what you borrowed.
If you’ve defaulted on an account, the best thing to do is to set up a repayment plan. Avoid borrowing any more until you’re more on top of your debts.