A "good negotiator" is someone who is skilled at finding solutions and making agreements with others. They can effectively communicate, understand different perspectives, and reach a satisfying outcome for all parties involved.
Clients appreciate his «practical legal advice» and also highlight him as «a very good negotiator with lots of deal experience.» (drinkerbiddle.com)
«One is about the product specifications and being really good negotiators with a lot of our vendors so we get the best price upfront. (fooddrink-magazine.com)
Without doubt I find women much better negotiators than men. (inc.com)