A savage who gets fed up with other people (8)
I believe the answer is:
cannibal
'a savage' is the definition.
(I know that cannibal is a type of savage)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for cannibal that I've seen before include "Animal that eats it own kid (8)." , "Animal that eats its own kind" , "Eater of one's own kind" , "One with odd eating habits" , "Person who eats human flesh" .)