Clunk vs Flunk - What's the difference?

As verbs the difference between clunk and flunk

is that clunk is to make such a sound while flunk is (us|ambitransitive) of a student, to fail a class; to not pass.

is a dull, metallic sound, especially one made by two bodies coming into contact.

(en noun)

a dull, metallic sound, especially one made by two bodies coming into contact

(en verb)

to make such a sound

(en verb)

(US, ambitransitive) Of a student, to fail a class; to not pass.

He flunked math, again.

(US) Of a teacher, to deny a student a passing grade.

Unsatisfied with Fred's progress, the teacher flunked him.

(US, dated, informal) To shirk (a task or duty).

To back out through fear.