Ready participant's offer (9)
I believe the answer is:
volunteer
This clue might be a double definition.
'ready participant's' is the first definition.
Both the answer and definition are adjectives. Maybe there's a link between them I don't understand?
'offer' is the second definition.
(synonyms)
Can you help me to learn more?
(Other definitions for volunteer that I've seen before include "Without being asked" , "Put forward, suggest" , "person working for free, perhaps" , "Offer one's services" , "Step forward" .)