nastygram /nas'tee-gram/ n.
1. A protocol packet or item of email (the latter is also
called a letterbomb) that takes
advantage of misfeatures or security holes on the target system
to do untoward things. 2. Disapproving mail, esp. from a net.god, pursuant to a violation of netiquette or a complaint about
failure to correct some mail- or news-transmission problem.
Compare shitogram, mailbomb. 3. A status report from an unhappy,
and probably picky, customer. "What'd Corporate say in today's
nastygram?" 4. [deprecated] An error reply by mail from a daemon; in particular, a bounce message.