The phrase 'leave on the cutting room floor' is a metaphor used to describe something that has been excluded or discarded. It originates from the film industry, where scenes that are not included in the final cut of a movie are literally left on the cutting room floor. In this context, the crossword solution 'OMIT' (4 letters) is a synonym for the phrase 'leave on the cutting room floor', meaning to exclude or discard something.