Single man’s club (4)
I believe the answer is:
iron
'club' is the definition.
(type of golf club)
'single man's' is the wordplay.
'single' becomes 'I' (one).
'man' becomes 'ron' (short for Ronald).
'i'+'ron'='IRON'
(Other definitions for iron that I've seen before include "Remove creases from" , "inflexible > club" , "Decrease" , "Smooth - driver?" , "Heavy metallic element" .)