First of all a sucker punch is when someone throws a sudden punch without warning, before the fight was meant to begin or after it’s over. Like if you’re in the ring for a fight and your opponent punches you before the bell rings to begin the fight. If you and your opponent have finished the fight and one of you suddenly throws a surprise punch then that would also be considered a sucker punch. This is not acceptable at all. A fight has its specific rules and regulations and should begin and end properly.