Abusive dereferencing refers to the act of accessing or manipulating a memory location that has been freed or is no longer valid. This can occur when a program attempts to use a pointer that points to an object that has been deleted or deallocated, resulting in unpredictable and potentially harmful behavior. It is considered an abusive practice as it violates the rules of proper memory management and can lead to crashes, data corruption, and security vulnerabilities. Proper handling of pointers and memory allocation is crucial to avoid abusive dereferencing and ensure the stability and security of a program.