shoo-in (n.): one that is a certain or easy winner

A few of the besties and I were watching the Oscars Sunday night when the indefatigable M.K. Mulkeen asked about the derivation of the lexeme “shoo-in,” possibly in reference to the nomination of “Click” for Best Makeup. None of us had an answer or even a hypothesis at the ready, but some cursory internet research indicates that the phrase derives from fixed horse races, in which there was only one possible winner, which horse need not even run directly to the finish line but could in fact be “shooed in” to the goal by a trainer, attendant, or unemployed slob.