Why Is The K-Nearest Neighbors (KNN) Called A "Lazy Algorithm"?

Understanding why K-Nearest Neighbors is called a "lazy learner" K-Nearest Neighbors or KNN is one of the simplest machine learning algorithms. This algorithm is very easy to implement and equally easy to understand. It is a supervised machine learning algorithm. This means we need a reference dataset to predict the category/group of the future data point. Once the KNN model is trained on the reference dataset, it classifies the new data points based on the points (neighbors) that are most similar to it.