The Collaborative International Dictionary
flunk out \flunk out\ v. i. to be dismissed (from a school or course of study) due to failure to perform up to the minimum standard.
Syn: fail out; wash out. [PJC]
Wiktionary
vb. 1 (context idiomatic English) To fail to finish school, or a given subject, program or course, due to academic shortcomings; i.e., to have too many flunking or failing grades (marks). 2 (context idiomatic English) (of an educator or institution) To impose failing grades on (a student), often requiring a retaking of the course or academic year.
Usage examples of "flunk out".
But if it meant you were going to do one or the other, like be a cum laude Graduate or flunk out altogether, there were plenty students like that in the old days, and nobody put them out to die on account of it.
Along about Thursday or Friday some boy who is about to flunk out anyhow will start thinking over the fact that Hendrick didn’.
Along about Thursday or Friday some boy who is about to flunk out anyhow will start thinking over the fact that Hendrick didn't get so very much, not even the number of lashes for drunken driving .
It worked so totally well--I have unlimited deferment now provided I don't give up my studies or flunk out.
So maybe I flunk out of school altogether and marry a millionaire and travel around the world on my own yacht.