Hire and participate (6)
I believe the answer is:
engage
I believe this clue is a double definition.
'hire' is the first definition.
(I know that hire can be written as engage)
'participate' is the second definition.
(I've seen this before)
'and' is the link.
(Other definitions for engage that I've seen before include "Hire (a worker)" , "Pay to serve" , "Employ or captivate" , "Take someone on as a worker" , "attack" .)