The most exceptional or memorable performance or item among others; a stand-out. Yeah, the opening act was a real show-stopper—the headlining band was disappointing in comparison!All the pieces in the designer's collection were excellent, but the wedding dress was a real show-stopper.
a show-stopper
a performance or part of a performance that is extremely good Her conference speech was a real show-stopper.
bullet-stopper
n. a U.S. Marine. (From the Persian Gulf War.) About a dozen bullet-stoppers came into the bar and the army guys tried to start a fight.
flopper-stopper
n. a brassiere. She’s very shy. She won’t even hang her flopper-stoppers out on the line to dry.