In sports, someone who shamelessly cheers for a particular team not because he likes them or follows them faithfully, but only because that particular team is the "popular" choice or has been or is the top team in their specific sport recently. When that team which bandwagoners follow falls from grace, they gleefully jump on the next teams bandwagon and cheer for that team.

A fan of a particular sports team who had no previous interest in the team until they began winning. They often will claim that they have been "a fan forever." You must discredit them on every statement they make.

In sports, someone who shamelessly cheers for a particular team not because he likes them or follows them faithfully, but only because that particular team is the "popular" choice or has been or is the top team in their specific sport recently. When that team which bandwagoners follow falls from grace, they gleefully jump on the next teams bandwagon and cheer for that team.

In sports, someone who selectively cheers for a particular team (Team A) not because he likes them or follows them faithfully, but only because another team (Team B) that he does not like, happens to be doing worse than Team A. This person then enjoys ridiculing fans of Team B, and often will claim that they have been "a fan forever", but only for the time being, because when Team B performs better than Team A, they then go back into hiding and remain silent.

Bandwagoner: Dallas Mavericks fans.