A monopolist is a

Price Acceptor Price Adjuster Price Setter Price Taker

Price Setter

A monopolist is a price setter or a price maker. He is the ONLY producer of the product. So if anyone wants to buy that product, he/she must do so from the monopolist only. This is unlike a perfectly competitive market where there are a large number of firms and so no single firm has power to influence market price. They have to be price takers.