Resolute golfer’s support for furniture item (6)
I believe the answer is:
settee
'for furniture item' is the definition.
(I've seen this in another clue)
'resolute golfer's support' is the wordplay.
'resolute' becomes 'set' (I've seen this in another clue).
'golfer's support' becomes 'tee' (I've seen this in another clue).
'set'+'tee'='SETTEE'
(Other definitions for settee that I've seen before include "Item of furniture" , "two-seater?" , "solver, might you say?" , "somewhere to sit" , "Multiple seat" .)