Angry at outset is returning rather inferior furniture item (9)
I believe the answer is:
irritable
'angry' is the definition.
(thesaurus)
'at outset is returning rather inferior furniture item' is the wordplay.
'at outset' suggests taking the first letters.
'furniture item' becomes 'table' (table is a type of item of furniture).
The initial letters of 'is returning rather inferior' is 'irri'.
'irri'+'table'='IRRITABLE'
(Other definitions for irritable that I've seen before include "Crabby" , "Crotchety" , "Sensitive" , "Testy" , "Easily annoyed" .)