In which situation can I use “shoo-in”?
A "shoo-in" is a person or object that has promise to succeed. In the context of a competition, it means they are likely to win the competition. When someone or something fits this criteria, you can say they are/were "a shoo-in" + what they are "a shoo-in" for, such as to win, for a job, to be elected, etc. This is a rare term and many native English speakers are not familiar with it, so I do not recommend using it in general. You can simply say "likely" instead. Ex: She was a shoo-in to become president. Ex: He is likely to get the job.