Get untidy to confound and upset most of distinguished party (8)
I believe the answer is:
dishevel
'get untidy' is the definition.
(to make dishevelled)
'confound and upset most of distinguished party' is the wordplay.
'confound' becomes 'dish' (dish can informally mean to defeat or confound).
'and' is a charade indicator (letters next to each other).
'upset' says the letters should be written in reverse.
'most of distinguished party' becomes 'leve' (I can't justify this - if you can you should believe this answer much more).
'leve' written backwards gives 'evel'.
'dish'+'evel'='DISHEVEL'
'to' acts as a link.
(Other definitions for dishevel that I've seen before include "Get ruffled" , "Make untidy" , "Disorder, ruffle" , "Disarrange - rumple" , "Ruffle (e.g. hair)" .)