Spoofing is an attack method where the attacker masquerades as a legitimate device or user to gain unauthorized access to resources, intercept communications, or distribute malware. This is central to understanding many cybersecurity threats and is a fundamental concept within the realm of penetration testing. ARP poisoning and DNS cache poisoning are specific techniques where spoofing is utilized, but they are not synonymous with spoofing in the broader sense. Masquerading is not typically used as a technical term in the context of security attacks.