:bonk/oif: /bonk/, /oyf/ interj. In the {MUD} community, it
has become traditional to express pique or censure by `bonking'
the offending person. Convention holds that one should acknowledge
a bonk by saying `oif!' and there is a myth to the effect that
failing to do so upsets the cosmic bonk/oif balance, causing much
trouble in the universe. Some MUDs have implemented special
commands for bonking and oifing. See also {talk mode}.
-- The AI Hackers Dictionary