Upsetting green friend, on the whole (9)
I believe the answer is:
generally
'on the whole' is the definition.
(thesaurus)
'upsetting green friend' is the wordplay.
'upsetting' indicates anagramming the letters.
'friend' becomes 'ally' (an ally is a friend or supporter).
'green' anagrammed gives 'gener'.
'gener'+'ally'='GENERALLY'
(Other definitions for generally that I've seen before include "Usually, as a rule" , "In most cases, usually" , "as usual" , "For the most part" , "In most cases, as a general rule" .)