"Blowout loss" refers to a big or significant defeat in a competition or game. It means that one team or person was greatly outperformed by their opponent, resulting in a substantial and clear victory for the opposing side. Full definition
Brazil's dreams of winning the World Cup as the host country were dashed in 2014 by a disastrous 7 - 1 blowout loss in the semifinals to Germany. (sbnation.com)
The Celtics are 1 — 3 against the Cavs this season, including a humiliating blowout loss at home near the end of this season that would have all but guaranteed them the number 1 seed had they won. (sbnation.com)
Mike Leach is pretty much the best air raid coach ever, and even he's seemed to peak at like 8 - 9 wins with blowout losses against every half decent defense his team faces (sbnation.com)