Wiktionary
undernet
n. The criminal underworld in cyberspace.
Wikipedia
Undernet
The Undernet is the fourth largest publicly monitored Internet Relay Chat (IRC) network, c. 2016, with about 19 client servers serving 17,444 users in 6621 channels at any given time.
IRC clients can connect to Undernet via the global round robin irc.undernet.org, the region-specific round robins us.undernet.org and eu.undernet.org, or a specific server from the server list.
Usage examples of "undernet".
The Undernet community hates having its servers frozen for any reason at any time.