The antonyms for the word "pro vender" are amateur, novice, rookie, and layman. These words refer to a person who lacks the skills, expertise, and experience to sell or promote products or services professionally. Unlike pro venders who are seasoned and knowledgeable in their field, amateurs and novices often struggle to market their goods and attract customers. Rookies may also find it challenging to navigate the complex world of sales and marketing. Laymen, on the other hand, have little or no knowledge of marketing techniques and principles. Thus, they may not be able to effectively sell products or services to potential clients.