Quick Definition
In cybersecurity, to be Pwned ("owned") is to have been the victim of a data breach or unauthorized privilege escalation.
In particular, the term is generally used in cases in which individual or system account(s) have been intentionally compromised by an attacker, rather than in cases of accidental or inadvertent data release.
The term originates in the gaming and hacker cultures of the 1990s, as users experiencing attacks or losses of one kind or another attempted to rapidly type "owned" in chats but instead accidentally hit the "p" key by mistake. In an early example of Internet meme and insider humor culture, the typo stuck.