cheerleader:
(plural: ‘cheerleaders‘; pronunciation: the letters ‘ch’ rhyme with the letters ‘ch’ in “church” — ‘cheer…leader’)

cheerleaders resting
a person who praises somebody or something more than they deserve;
(mostly in the USA) a person, a young woman, who cheers (shows happiness by jumping and clapping) a player or a team in an outdoor game, especially at a foot- ball game, and these days at a cricket match;
a person who speaks highly of somebody or something so that others are excited and influenced,

cheerleaders in action
Sara was the best cheerleader for the school basketball team when she was a student.
Mathew has become a cheerleader for the alternative medicine. (i.e. she talks to everybody about the benefits of following the alternative medicine)
Khan has objected to some of the hockey cheerleaders wearing very short skirts.
The failed cheerleader for global warming, Al Gore, is now accused of misleading the public by showing fake documents and scientific finding.
