What legal term describes a seller who does not have the right to bid on their own property at a specific type of auction?

In the context of auctions, the term that best describes a seller who does not have the right to bid on their own property is "consignee." This term refers to a person or entity (the consignor in this case) that allows another party (the consignee) to sell their goods on their behalf. In specific auction settings, particularly in regulated or formal auctions, the seller's right to bid on their items can be restricted to ensure fair competition among bidders. By designating the seller as a consignee, it emphasizes their role without granting them the ability to influence the bidding process through their own bids, which could create conflicts of interest and undermine the integrity of the auction.

The other terms do not specifically capture this scenario. A principal generally refers to the main party involved in a transaction, while a bidder is a participant in the auction who makes offers to purchase an item. A purchaser is the individual who successfully buys an item at the auction. None of these roles specifically highlights the limitation placed on a seller's ability to bid on their own property. Thus, "consignee" is the most accurate term for the context presented in the question.