black hat

noun

: a hacker who infiltrates a computer system for malicious purposes (as to disable a website or uncover secret information)

In one segment … Assange reflects on his work as a black hat hacker in the early 1990s, recalling wistfully how he and others hacked into the Pentagon's Security Coordination Center.

—Kim Zetter

compare white hat

Word History

First Known Use

1990, in the meaning defined above