Handle king, then aristocrat (4)
I believe the answer is:
knob
'handle' is the definition.
(I know that knob is a type of handle)
'king then aristocrat' is the wordplay.
'king' becomes 'K' (chess abbreviation).
'then' says to put letters next to each other.
'aristocrat' becomes 'nob' (nob can mean an aristocrat).
'k'+'nob'='KNOB'
(Other definitions for knob that I've seen before include "Round door-handle" , "Rounded projection" , "Turn it to open door" , "Round door handle or lump of butter" , "Little group of wildfowl" .)