flunk out

Wiktionary

1. v. idiomatic To fail to finish school, or a given subject or course, due to academic shortcomings; i.e., to have too many flunking or failing grades (marks).
2. v. idiomatic (of an educator or institution) To impose failing grades on (a student), often requiring a retaking of the course or academic year.

GNU Webster's 1913

1. v. to be dismissed (from a school or course of study) due to failure to perform up to the minimum standard.