The crossword solution for the term 'Boot-Camp Sentence Ender' is SIR, which is an acronym for 'Statement of Intent to Register'. This is a form that must be completed by students who wish to register for a boot camp. It is used to provide information about the student's background and goals for the boot camp. The form also serves as a contract between the student and the boot camp provider, outlining the expectations and responsibilities of both parties.