Single — golden oldie’s inside spinning (4)
I believe the answer is:
lone
'single' is the definition.
('lone' can be a synonym of 'single')
'golden oldie's inside spinning' is the wordplay.
'inside' indicates the answer is hidden within the clue.
'spinning' says the letters should be written in reverse.
'enol' is hidden within 'golden oldies'.
'enol' written backwards gives 'LONE'.
(Other definitions for lone that I've seen before include "He likes to operate by himself" , "Unaccompanied" , "The ... Ranger, fictional masked cowboy" , "Sole" , "Companionless" .)