A degenerate bilinear form is like playing with Legos, but sometimes when you put two pieces together, they don't stick.
Now, bilinear forms are like playing with two Legos at once. You have a Lego boat and a Lego car, and you want to put them together in a way that makes sense. But sometimes, when you try to fit them together, they don't quite match up.
A degenerate bilinear form is like that - when you try to fit two Legos together, they don't stick. In other words, there are some pairs of inputs that don't produce any output.
For example, let's say you're playing with a bilinear form that takes in two numbers and multiplies them together. If you put in the numbers 7 and 0, you get 0 as your output - this is an example of a degenerate bilinear form because one of the inputs produces no output.
So, a degenerate bilinear form is just a special kind of bilinear form where some inputs don't produce any output when you put them together. It's like trying to fit two Lego pieces together and they just won't connect - you can keep trying, but it's just not going to work!