If he doesn't find a solution to his problem soon, he'll surely flunk out of college.

如果他不能很快找到解决问题的办法，他肯定要被学院退学。

《柯林斯英汉双解大词典》

But just like high school, many students flunk out of college because of their poor grades.

但正如高中一样，许多大学生因成绩不好而退学。

youdao

Asked at the start of the test, if would-be motorists flunk the questions it will count as one driving fault out of the maximum of 15 allowed before a fail.

BBC: L-plate