Easily angered, he had to tangle with editor (9)
I believe the answer is:
hotheaded
'easily angered' is the definition.
'he had to tangle with editor' is the wordplay.
'tangle' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'editor' becomes 'ed'.
'he'+'had'+'to'='hehadto'
'hehadto' anagrammed gives 'hothead'.
'hothead'+'ed'='HOTHEADED'
(Other definitions for hotheaded that I've seen before include "Explosive" , "rash" , "Irresponsible" .)