Is a Grade C bad on CeX?

Excuse me, I was wondering if you could clarify something for me. I recently saw a product rating as "Grade C" on CeX, and I'm not entirely sure what that means. Would you say that a Grade C rating on CeX is indicative of a product in poor condition or is it more of a subjective grading system? Could you elaborate on what I might expect from a product with this rating in terms of its physical appearance and functionality? I'm considering making a purchase but I want to be sure I understand the grading system before committing.