Quiz: Remember the definition of mal de mer?
(By analogy with "trufan" from SF fandom) One who exemplifies the primary values of hacker culture, especially competence and helpfulness to other hackers. A high compliment. "He spent 6 hours helping me bring up UUCP and netnews on my FOOBAR 4000 last week - manifestly the act of a true-hacker".
Compare demigod, opposite: munchkin.