Couriers on contract? (6)
I believe the answer is:
riders
'couriers on contract?' is the definition.
The definition and answer can be both people as well as being plural nouns.
Perhaps there's a link between them I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for riders that I've seen before include "Supplementary clauses" , "Horse travellers" , "Jockeys" , "Synge play '. . . . . . to the Sea" , "Clauses appended to legislative bills" .)