Proposal (4)
'proposal' is the definition.
(idea can mean a proposal or suggestion)
This is all the clue.
(Other definitions for idea that I've seen before include "Creative spark" , "Notion in the mind" , "Mental impression" , "Aim" , "Clue" .)
'proposal' is the definition.
(an offer is a proposal or suggestion)
This is the entire clue.
(Other definitions for offer that I've seen before include "Put forward" , "Tender - proposal" , "Submit" , "Bid; proposal" , "Suggest" .)
'proposal' is the definition.
(a bid is a proposal or offer)
This is all the clue.
(Other definitions for bid that I've seen before include "Offer (for); demand" , "Tender (for work)" , "Sum offered at an auction" , "Offer; command" , "Take part in auction" .)