COON

It used to be used in the slave and jim crow days as an equivalent to nigger or nigga, so basically used to bring black people down.
It is now used by black people to describe a black person who is a uncle tom type figure. They put down their own people because of self hate or to please massa (the white man/woman)

"girl that man said black people are just a group of thugs and need to do better"
"huh??? ISTG that nigga a coon"