Caliban upset about new man-eater? (8)
I believe the answer is:
cannibal
'man-eater?' is the definition.
(I know that man-eater can be written as cannibal)
'caliban upset about new' is the wordplay.
'upset' indicates an anagram.
'about' is an insertion indicator.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'caliban' anagrammed gives 'canibal'.
'canibal' going around 'n' is 'CANNIBAL'.
(Other definitions for cannibal that I've seen before include "Anthropophagite" , "Fellow consumer" , "Person eating human flesh" , "Animal that eats it own kid (8)." , "Animal that eats its own kind" .)