Deathmatch, sometimes specifically one in which every player is pitted against all the others.
Chaos; a chaotic situation lacking rules or control.
Open to anyone and with no or few rules.
In American football or Canadian football, a play that begins with a snap from the center while opposing teams are on either side of a line of scrimmage.
A rough fight.
In some team sports, especially soccer, a practice game which does not count on a team's record.
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To have, or be involved in, a scrimmage.