flunk 
/ˈflʌŋk/ verb
flunks; flunked; flunk·ing /ˈflʌŋk/ verb US, informal 1 : to get a failing grade in (something, such as an examination or course) : fail [+ obj] ▪ If I flunk this class, I have to take it over again. ▪ flunk a test [no obj] ▪ If I flunk, I have to take this class over again. 2 [+ obj] : to give a failing grade to (someone) : fail
▪ The teacher had to flunk two students.
▪ The teacher had to flunk two students.
flunk out
[phrasal verb] US, informal : to be required to leave a school because you have failed your courses
▪ He tried going to college, but he flunked out after one year. — often + of ▪ He flunked out of college.
▪ He tried going to college, but he flunked out after one year. — often + of ▪ He flunked out of college.
