Openweight is a weight that does not limit the weight. It is also called indiscriminate.
MMA
In mixed martial arts there is an unlimited charge for ROAD FC, Pancrase, ZST, and DEEP. DREAM, now missing, had an unlimited number of titles entitled "Super Hulk Tournament - World Superhuman Championship". In the case of Pancrase, the super heavyweight, the heaviest weight class, was abolished and incorporated into the unlimited amount. In DEEP, we played unlimited under the name megaton, and over 100kg players were confronted, but the first champion was Yusuke Kawaguchi, less than 100kg.
References
Openweight Wikipedia(Text) CC BY-SA