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1.
A person who gets a crowd psyched up by being the first one to clap or to shout.
Also a person who claps and shouts, at a small concert or show, enough to replace a small cheering crowd.
Man, that show tonight had a rough crowd, at least Gary was there to get them to start cheering, he's a one-man crowd!
by DINOLazar August 19, 2010