If the referee feels that a fighter has conducted themselves in an unsportsmanlike manner, they may stop the action of the fight to deduct points or stop the bout to disqualify the fighter.
No contest decisions in mixed martial arts (MMA) are usually declared when an accidental illegal strike (the rules on which differ from each organization) causes the recipient of the blow to be unable to continue, that decision being made by the referee, doctor, the fighter or his corner.