Press joins small clubs (5)
I believe the answer is:
irons
'clubs' is the definition.
(iron is a kind of club)
'press joins small' is the wordplay.
'press' becomes 'iron' (ironing is a kind of pressing).
'joins' says to put letters next to each other.
'small' becomes 's' (abbreviation - e.g. clothes size).
'iron'+'s'='IRONS'
(Other definitions for irons that I've seen before include "Metal-headed golfclubs" , "in which one is restrained" , "Fetters, handcuffs" , "One might have too many in the fire" , "Metal shackles and golf clubs" .)