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Someone who joins or supports something, usually a sports team, only after it is successful or popular. I can't stand the bandwagon fans who've come out of the woodwork now that the team is winning. Where were they during last year's awful season? I'm no bandwagon fan—I support these guys no matter what, win or lose!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.