To explain what is Fool's Mate. We can refer to the great Wikipedia for its definition.
"The fool's mate can be achieved only by Black, giving checkmate on the second move with the queen. The fool's mate received its name because it can occur only if White commits an extraordinary blunder. Even among rank beginners, this checkmate rarely occurs in practice."
Simple Fool's Mate
Let's take a look at what Fool's Mate looks like.
https://lichess.org/study/MVftwNj8/oknLf6pJ#4
What you see in the position, Black checkmated White because White blunders Mate In 1 and there is no way to save the position. Therefore, it is called Fool's Mate.
Fool's Mate Study
Lucky for you, if you want to learn about it. I actually have created a quick study on Fool's Mate (for people that are interested). I have given some examples of positions there. Feel free to check them out!
