Used as support worker (6,4)
I believe the answer is:
second hand
'used' is the definition.
(I've seen this before)
'support worker' is the wordplay.
'support' becomes 'second' (eg to second an idea is to support it).
'worker' becomes 'hand' (hand is a kind of worker).
'second'+'hand'='SECOND-HAND'
'as' is the link.
(Other definitions for second hand that I've seen before include "Previously owned - part of watch" , "going quickly on the clock?" , "Pointer on dial" , "Part of a timepiece" , "Pre-owned - used" .)