Everybody I have upset scoffed, revealing temper (9)
I believe the answer is:
alleviate
'temper' is the definition.
(thesaurus)
'everybody i have upset scoffed' is the wordplay.
'everybody' becomes 'all' (I've seen this before).
'i have' becomes 'ive'.
'upset' says the letters should be written backwards.
'scoffed' becomes 'ate' ('to scoff' is to eat).
'ive' backwards is 'evi'.
'all'+'evi'+'ate'='ALLEVIATE'
'revealing' is the link.
(Other definitions for alleviate that I've seen before include "Make light" , "Relieve" , "Lessen strength of" , "dull" , "Make (pain) less intense" .)