Being a substitute is a job that involves taking the place of someone else for a short period of time. It can involve filling in for an absent teacher, or taking over a shift at work. The term 'Be a Substitute' can be broken down into two words: 'REPLACE' and 'Stepin'. REPLACE is a 7 letter word meaning to take the place of someone or something else, while Stepin is a 6 letter word meaning to take the place of someone else temporarily.