Chairman essentially supported by small number around club (4)
I believe the answer is:
iron
'club' is the definition.
(type of golf club)
'chairman essentially supported by small number around' is the wordplay.
'essentially' indicates the central letters.
'supported by' is a charade indicator (letters next to each other) (in a down clue, some letters hold up others).
'small number' becomes 'no' (abbreviation for 'number'; 'small' indicates an abbreviation).
'around' says the letters should be written backwards.
The middle of 'chairman' is 'ir'.
'no' in reverse letter order is 'on'.
'ir'+'on'='IRON'
(Other definitions for iron that I've seen before include "Metal (that may be wrought)" , "Metallic chemical element" , "Smoother - metal" , "Strong metal; golf club" , "Wellington was known as the .... Duke" .)