Sidles out, upset and abandoned (9)
I believe the answer is:
dissolute
'abandoned' is the definition.
(thesaurus)
'sidles out upset' is the wordplay.
'upset' is an anagram indicator.
'sidles'+'out'='sidlesout'
'sidlesout' is an anagram of 'DISSOLUTE'.
'and' acts as a link.
(Other definitions for dissolute that I've seen before include "Sensually overindulgent" , "Duelist so (anag) - debauched" , "O, lust dies when one is this loose in morals" , "Sensually overindugent" , "Old tissue (anag) - like a rake?" .)