Call up, be upset at fault (8)
I believe the answer is:
culpable
'at fault' is the definition.
(thesaurus)
'call up be upset' is the wordplay.
'upset' is an anagram indicator.
'call'+'up'+'be'='callupbe'
'callupbe' is an anagram of 'CULPABLE'.
(Other definitions for culpable that I've seen before include "Deserving blame" , "Proboscis" , "Guilty" , "Answerable" , "Blameworthy, censurable" .)