Hi kiddo!
Have you ever seen a tree with different branches and leaves? Those bunches of branches and leaves are called decision tree. They are used to make decisions based on certain conditions.
Now, imagine if we had a tiny decision tree with only one branch and two leaves. This tiny tree is called a decision stump.
Let's say we have two options to choose from: eat an apple or a banana. We can create a decision stump by asking a simple question: Is the fruit an apple? If the answer is "Yes", then the decision is to eat the apple. If the answer is "No ", the decision is to eat the banana.
So basically, a decision stump is a mini decision tree with only one question and two possible outcomes. It is used in machine learning algorithms to make fast and easy decisions based on simple rules.
Hope it makes sense to you now!