From Longman Dictionary of Contemporary Englishspectator sportspecˈtator ˌsport / $ ˈ... ˌ./ noun [countable] 1 DSa sport that people go and watch2 something that you watch rather than take part in – usually used humorously Life is not a spectator sport.
Examples from the Corpus
spectator sport• Rugby has become big business and a spectator sport.• Mathematics is not a spectator sport.• Sport may be taken too seriously; high-performance spectator sport is arguably too central to our lives already.• More than £1 billion is bet on greyhound racing each year in what is Britain's most popular spectator sport.• Marina took charge of Lucy, and she relaxed: Marina drawing people out was spectator sport. 