Used to connect supporter with worker (6)
'worker' is the definition.
(second is a kind of worker)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for second that I've seen before include "additional > support" , "Back-up; short time" , "Time for a supporter" , "A duellist's or boxer's assistant" , "Unsurpassed" .)
Can you help me to learn more?
(Other definitions for second-hand that I've seen before include "Used" , "Not new - part of watch!" , "Not original" , "Previously owned - part of watch" .)