The game is typically very one sided, despite the games being created under the false impression that it is going to be 'fair'.
Can apply to any team-oriented game, but the term is likely to have originated in DotA.
Can also be used as a noun, whereby the events described above occurs.
"5v5 noobs only. nothing suss"
When organized groups of confidently good players go to a cybercafe/ventrilo and team up against random pub players with no prior association.