When referring to a student who is no longer enrolled in a school, there are several synonyms that can be used instead of the commonly used "former student". Some of these synonyms include "graduate", "alumnus" (for male), "alumna" (for female), "ex-student", "past pupil", and "former attendee". These terms are all interchangeable and can be used depending on the context. For instance, if a school wants to send invitations to its alumni, it would use the terms "alumnus" and "alumna". On the other hand, if a school wants to refer to a student who left the school without graduating, they could use "ex-student" or "former attendee".