To flunk is to fail or not perform as expected. This is a term used for performance in school among students, but it can also be applied to situations outside of education.
I flunked my test.
Gabriel is afraid he’s going to flunk his final exam.
Diane flunked out of med school.
If you don’t want to flunk out of school, you have to study.
Yussuf is flunking his math class.
Ms. Roberts has a reputation for flunking her students. (A student flunks the test; the teacher flunks the student.)
What are you going to do if you flunk your driving test?
The president of the company is flunking his responsibilities.
As an adjective, the word "flunky" is used for a person who does the dirty work of a boss or a superior.
The President seems to remain above the law while his flunkies go to jail.
The orders to ship the stolen merchandise were carried out by flunkies to the boss.
