Short Definition
Binary classification is a prediction task where each example belongs to one of two classes.
Intuition
The model answers a yes-or-no question, such as fraud or not fraud, spam or not spam, approved or rejected.
Technical Definition
Binary classification estimates a decision boundary or probability for two mutually exclusive target classes.
Example
A content moderation model may classify a message as policy-violating or allowed.
Common Misunderstandings
Binary classification still needs threshold selection.
A probability score and a final class decision are different outputs.