The phrase "runaway success" means something that becomes extremely popular or successful very quickly, often beyond what was expected or predicted. Full definition
It's a gorgeous runaway success of a book filled with beautiful, Middle Eastern inspired vegetarian dishes so choosing what to cook was difficult. (hungryaustralian.com)
Young Adult Fiction is enjoying a tremendous amount of popularity for the last few years with runaway success like The Hunger Games by Suzanne Collins and Rick Riordan's Percy Jackson series. (goodereader.com)
While it's perhaps not the kind of runaway success story True & Co. may have been chasing, the deal reflects a larger trend: to better secure their futures, those being disrupted — traditional old - guard incumbents — are increasingly buying tech - enabled disruptors. (businessoffashion.com)