Bid; volunteer (5)
I believe the answer is:
offer
I believe this clue is a double definition.
'bid' is the first definition.
(I know that bid can be written as offer)
'volunteer' is the second definition.
(I know that volunteer can be written as offer)
(Other definitions for offer that I've seen before include "Present for acceptance or rejection" , "hand" , "Attempt" , "Propose (to give)" , "Tender for acceptance" .)