1. The ability to be sold or transferred to another party as a form of payment. Something which is negotiable is transferable by endorsement and delivery. A negotiable instrument could be a check made out to you, because you could endorse it for payment to you or transfer it to someone else as payment to them. 2. For a price or other terms of a contract or agreement, the ability to be adjusted. For example, when a price is said to be negotiable, it means that the seller is open to the possibility of reducing the price.